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Canada FluWatch Weekly Reports 2015-2016 Season Weeks 21-24

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  • #16
    FluWatch report: March 27 to April 2, 2016 (week 13)

    Overall Summary

    • Influenza activity peaked nationally in week 10; however, lower but sustained activity is being reported throughout the country.
    • Most regions of Canada reported sporadic or localized influenza activity.
    • Compared to the previous two weeks, there was an increase in the number of provincial and territorial hospitalizations reported in week 13 but the number reported (353) remains below the week 10 peak.
    • The number of influenza B detections is increasing, while influenza A detections are decreasing. Overall, laboratory detections of influenza are steadily decreasing.
    • Hospitalizations, ICU admissions and deaths among the pediatric population, while declining, remain above expected levels based on the past several influenza seasons.
    • For more information on the flu, see our Flu(influenza) web page.

    Download the alternative format
    (PDF format, 863 KB, 9 pages)
    Organization: Public Health Agency of Canada
    Date published: 2016-04-08

    Related Topics



    Are you a primary health care practitioner (General Practitioner, Nurse Practitioner or Registered Nurse) interested in becoming a FluWatch sentinel for the 2015-16 influenza season? Contact us at FluWatch@phac-aspc.gc.ca


    On this page

    Influenza/Influenza-like Illness Activity (geographic spread)

    In week 13, influenza activity was reported in all but four regions of Canada. A total of 23 regions reported localized activity levels across the country. Sporadic influenza/ILI activity was reported in 26 regions across Canada.
    Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, week 13




    Note: Influenza/ILI activity levels, as represented on this map, are assigned and reported by Provincial and Territorial Ministries of Health, based on laboratory confirmations, sentinel ILI rates and reported outbreaks. Please refer to detailed definitions at the end of the report. Maps from previous weeks, including any retrospective updates, are available in the mapping feature found in the Weekly Influenza Reports.
    Figure 1 - Text Description Laboratory Confirmed Influenza Detections

    In week 13, the percent positive for influenza continued to decrease from the previous week [from 30% in week 12 to 28% in week 13] (Figure 2). Compared to the previous five seasons, the percent positive (28%) reported in week 13 was above the five year average for that week and exceeded the expected levels (range 12.0%-17.9%). With the late start to the 2015-16 influenza season, these above normal levels are not unexpected.
    Figure 2. Number of positive influenza tests and percentage of tests positive, by type, subtype and report week, Canada, 2015-16

    Figure 2 - Text Description In week 13, there were 2,837 positive influenza tests reported. The number of positive influenza B tests reported is accounting for an increasing proportion of all positive influenza tests reported. This week, influenza B accounted for 36% of all positive tests. To date, 80% of influenza detections have been influenza A and among those subtyped, the vast majority have been influenza A(H1N1) [91% (10155/11124)].
    Figure 3. Cumulative numbers of positive influenza specimens by type/subtype and province, Canada, 2015-16

    Note: Specimens from NT, YT, and NU are sent to reference laboratories in other provinces. Cumulative data includes updates to previous weeks.
    Figure 3 - Text Description To date this season, detailed information on age and type/subtype has been received for 27,158 cases. Children and teenagers (0-19 years of age) accounted for almost one third of all influenza cases (32%). Children (0-19), young adults (20-44) and middle-aged adults (45-64) accounted for approximately an equal proportion of influenza A(H1N1) cases (28%).
    Table 1 - Footnote 1 Table 1 includes specimens for which demographic information was reported. These represent a subset of all positive influenza cases reported.
    Return to Table 1 - Footnote1referrer
    Table 1 - Footnote 2 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections.
    Return to Table 1 - Footnote2referrer
    Table 1 - Footnote 3 Unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available.
    Return to Table 1 - Footnote3referrer
    Table 1 - Footnote x Suppressed to prevent residual disclosure.
    Return to Table 1 - Footnotexreferrer
    171 30 <5 Table 1 - Footnotex 129 4127 1650 63 2414 895 5023 18%
    56 9 0 47 196 2226 984 92 1150 1660 3887 14%
    209 52 <5 Table 1 - Footnotex 155 5387 2595 146 2646 1403 6790 25%
    287 79 0 208 73 5747 2549 175 3023 646 6393 24%
    262 60 <5 Table 1 - Footnotex 118 4233 1437 376 2420 832 5065 19%
    985 230 6 749 671 21720 9215 852 11653 5436 27158 100%
    59% 23% 1% 76% 41% 80% 42% 4% 54% 20%
    For data on other respiratory virus detections see the Respiratory Virus Detections in Canada Report on the Public Health Agency of Canada website.
    Influenza-like Illness Consultation Rate

    The national ILI consultation rate increased slightly from the previous week from 43.6 per 1,000 patient visits in week 12, to 45.2 per 1,000 patient visits in week 13. The highest ILI consultation rate was found in the 0-4 years age group (69.7 per 1,000) and the lowest was found in the ≥65 years age group (35.2 per 1,000) (Figure 4).
    Figure 4. Influenza-like-illness (ILI) consultation rates by age group and week, Canada, 2015-16

    Delays in the reporting of data may cause data to change retrospectively. In BC, AB, and SK, data are compiled by a provincial sentinel surveillance program for reporting to FluWatch. Not all sentinel physicians report every week.
    Figure 4 - Text Description Pharmacy Surveillance

    During week 13, the proportion of prescriptions for antivirals increased slightly to 78.6 antiviral prescriptions per 100,000 total prescriptions, which is slightly higher than the five year historical average for week 13. The proportion of prescriptions for antivirals remains highest among children. In week 13, the proportion reported among children was 162.4 per 100,000 total prescriptions.
    Figure 5. Proportion of prescription sales for influenza antivirals by age group and week, Canada, 2015-16

    Note: Pharmacy sales data are provided to the Public Health Agency of Canada by Rx Canada Inc. and sourced from major retail drug chains representing over 3,000 stores nationwide (excluding Nunavut) in 85% of Health Regions. Data provided include the number of new antiviral prescriptions (for Tamiflu[oseltamivir] and Relenza [zanamivir]) and the total number of new prescriptions dispensed by Province/Territory and age group.
    * The average weekly proportion includes data from April 2011 to March 2015.
    Figure 5 - Text Description Influenza Outbreak Surveillance

    In week 13, 21 new laboratory confirmed influenza outbreaks were reported: 12 in long-term care facilities (LTCF), five in hospitals and four in institutions or community settings. Of the outbreaks with known strains or subtypes, three outbreaks were due to influenza B, two outbreaks were due to influenza A(H1N1), one outbreak was due to influenza A(H3N2) and three were due to influenza A(UnS). Additionally, one ILI outbreak was reported in a school.
    To date this season, 354 outbreaks have been reported. At week 13 in the 2014-15 season, 1,527 outbreaks were reported and in the 2013-14 season,184 outbreaks were reported.
    Figure 6. Overall number of new laboratory-confirmed influenza outbreaksFigure 5 - Footnote1 by report week, Canada, 2015-2016

    Figure 6 - Footnote 1 All provinces and territories except NU report influenza outbreaks in long-term care facilities. All provinces and territories with the exception of NU and QC report outbreaks in hospitals. Outbreaks of influenza or influenza-like-illness in other facilities are reported to FluWatch but reporting varies between jurisdictions. Outbreak definitions are included at the end of the report.
    Return to Figure 5 - Footnote1referrer
    Figure 6 - Text Description Sentinel Pediatric Hospital Influenza Surveillance

    Paediatric Influenza Hospitalizations and Deaths

    Hospitalizations reported by the the Immunization Monitoring Program Active (IMPACT) network continue to decrease (Figure 7). In week 13, 61 hospitalizations were reported. The largest proportion of hospitalizations were in children aged 0-2 years, accounting for 38% of the hospitalizations. The majority of hospitalizations in week 13 were due to influenza A (57%); however, the proportion of weekly hospitalizations due to influenza B has been increasing steadily since week 08.
    To date this season, 1,075 laboratory-confirmed influenza-associated pediatric (≤16 years of age) hospitalizations have been reported by the IMPACT network: 822 hospitalized cases (76%) were due to influenza A and 253 cases (24%) were due to influenza B. The greatest proportion of hospitalized cases were in children aged 0-2 years (41 %). To date, 180 intensive care unit (ICU) admissions have been reported. Children aged 2 to 4 and 5 to 9 years each accounted for 27% of ICU admissions. A total of 113 ICU cases (62%) reported at least one underlying condition or comorbidity. Eight influenza-associated deaths have been reported.
    Table 2 - Footnote x Suppressed to prevent residual disclosure.
    Return to Table 2 - Footnotexreferrer
    110 32 5 73 19 129 (12%)
    251 72 7 172 57 308 (29%)
    236 76 <5 Table 2 - Footnotex 61 297 (28%)
    172 46 <5 Table 2 - Footnotex 81 253 (24%)
    53 18 <5 Table 2 - Footnotex 35 88 (8%)
    822 244 20 558 253 1075 (100%)
    Figure 7. Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2015-16, paediatric and adult hospitalizations (≤16 years of age, IMPACT; ≥16 years of age, CIRN-SOS)

    Not included in Table 2 and Figure 7 are two IMPACT cases that were due to co-infections of influenza A and B.
    Figure 7 - Text Description Adult Influenza Hospitalizations and Deaths

    In week 13, 73 hospitalizations were reported by the Canadian Immunization Research Network Serious Outcome Surveillance (CIRN-SOS) (Figure 7). The largest proportion of hospitalizations was in adults 65+ years of age (51%) and due to influenza A (73%).
    To date this season, 898 laboratory-confirmed influenza-associated adult (≥16 years of age) hospitalizations have been reported by CIRN-SOS (Table 3). The majority of hospitalized cases were due to influenza A (85%) and the largest reported proportion was among adults ≥65 years of age (49%). One hundred and thirty intensive care unit (ICU) admissions have been reported. A total of 69 ICU cases reported to have at least one underlying condition or comorbidity. A total of 32 deaths have been reported this season with the majority of deaths reported in adults ≥65 years of age (63%).
    Table 3 - Footnote x Suppressed to prevent residual disclosure.
    Return to Table 3 - Footnotexreferrer
    Table 3 - Footnotex <5 0 <5 <5 6 (1%)
    118 35 <5 Table 3 - Footnotex 27 145 (16%)
    274 78 <5 Table 3 - Footnotex 29 303 (34%)
    363 81 21 261 76 439 (49%)
    <5 0 0 <5 <5 5 (1%)
    764 200 25 539 134 898
    85% 26% 3% 71% 15% 100%
    Figure 8. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group (≥16 year of age), Canada 2015-16

    Note: The number of hospitalizations reported through CIRN-SOS and IMPACT represents a subset of all influenza-associated adult and paediatric hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
    x - Suppressed to prevent residual disclosure.
    Figure 8 - Text Description Provincial/Territorial Influenza Hospitalizations and Deaths

    In week 13, 353 hospitalizations were reported by participating provinces and territoriesFootnote*. The majority of hospitalizations were due to influenza A (78%). The largest proportion of cases reported in week 13 was in adults 65+ years of age (35%).
    Since the start of the 2015-16 season, 3,990 laboratory-confirmed influenza-associated hospitalizations have been reported. A total of 3,401 hospitalizations (85%) were due to influenza A and 589 (15%) were due to influenza B. Among cases for which the subtype of influenza A was reported, 93% (1601/1715) were influenza A(H1N1). The largest proportion (30%) of hospitalized cases were ≥65 years of age, followed closely by adults 45-64 years of age (27%). Three hundred and ninety-four ICU admissions have been reported of which 225 (57%) were due to influenza A(H1N1) and 183 (46%) were in the 45-64 age group. A total of 161 deaths have been reported; all but 14 were associated with influenza A. Adults ≥65 years of age represent 49% of reported deaths.
    Figure 9. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada 2015-16

    Figure 9 - Text Description Footnote * Note: Influenza-associated hospitalizations are not reported to PHAC by the following Provinces and Territory: BC, NU, and QC. Only hospitalizations that require intensive medical care are reported by SK. ICU admissions are not distinguished among hospital admissions reported from ON. Data may also include cases reported by the IMPACT networks. The number of new influenza-associated hospitalizations and deaths reported for the current week may include cases from ON that occurred in previous weeks, as a result of retrospective updates to the cumulative total. It is important to note that the hospitalization or death does not have to be attributable to influenza, a positive laboratory test is sufficient for reporting.
    Return to footnote*referrer
    Footnote * Includes three hospitalizations for which age is unknown.
    Return to footnote1referrer
    See additional data on Reported Influenza Hospitalizations and Deaths in Canada: 2011-12 to 2015-16 on the Public Health Agency of Canada website.
    Influenza Strain Characterizations

    During the 2015-16 influenza season, the National Microbiology Laboratory (NML) has characterized 1442 influenza viruses [159 A(H3N2), 857 A(H1N1) and 426 influenza B].
    Influenza A (H3N2): When tested by hemagglutination inhibition (HI) assays, 40 H3N2 viruses were antigenically characterized as A/Switzerland/9715293/2013-like using antiserum raised against cell-propagated A/Switzerland/9715293/2013.
    Sequence analysis was done on 119 H3N2 viruses. All viruses belonged to a genetic group for which most viruses were antigenically related to A/Switzerland/9715293/2013. A/Switzerland/9715293/2013 is the A(H3N2) component of the 2015-16 Northern Hemisphere's vaccine.
    Influenza A (H1N1): A total of 857 H1N1 viruses characterized were antigenically similar to A/California/7/2009, the A(H1N1) component of the 2015-16 influenza vaccine.
    Influenza B: A total of 112 influenza B viruses characterized were antigenically similar to the vaccine strain B/Phuket/3073/2013. A total of 314 influenza B viruses were characterized as B/Brisbane/60/2008-like, one of the influenza B components of the 2015-16 Northern Hemisphere quadrivalent influenza vaccine.
    The recommended components for the 2015-2016 northern hemisphere trivalent influenza vaccine include: an A/California/7/2009(H1N1)pdm09-like virus, an A/Switzerland/9715293/2013(H3N2)-like virus, and a B/Phuket/3073/2013 -like virus (Yamagata lineage). For quadrivalent vaccines, the addition of a B/Brisbane/60/2008-like virus (Victoria lineage) is recommended.
    The NML receives a proportion of the influenza positive specimens from provincial laboratories for strain characterization and antiviral resistance testing. Characterization data reflect the results of haemagglutination inhibition testing compared to the reference influenza strains recommended by WHO.

    .../

    "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerable citizens in our society, a life free of violence and fear."
    -Nelson Mandela

    Comment


    • #17
      FluWatch report: April 3 to April 9, 2016 (week 14)

      Overall Summary

      • Influenza activity peaked nationally in in the second week of March; however, lower but sustained activity is being reported throughout the country.
      • All regions of Canada reported sporadic or localized influenza activity.
      • Both influenza B and influenza A detections decreased in week 14. To date this season, a total of 34,105 positive influenza tests have been reported.
      • Hospitalizations, ICU admissions and deaths among the pediatric population, while declining, remain above expected levels based on the past several influenza seasons.
      • Despite higher pediatric hospitalizations reported, the pediatric population account for the smallest proportion of all deaths reported.
      • For more information on the flu, see our Flu(influenza) web page.

      Download the alternative format
      (PDF format, 869 KB, 9 pages)
      Organization: Public Health Agency of Canada
      Date published: 2016-04-15

      Related Topics



      Are you a primary health care practitioner (General Practitioner, Nurse Practitioner or Registered Nurse) interested in becoming a FluWatch sentinel for the 2015-16 influenza season? Contact us at FluWatch@phac-aspc.gc.ca


      On this page

      Influenza/Influenza-like Illness Activity (geographic spread)

      In week 14, influenza activity was reported in 50 regions across Canada. A total of 30 regions reported sporadic activity levels, while the remaining 20 reported localized activity levels.
      Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, week 14




      Note: Influenza/ILI activity levels, as represented on this map, are assigned and reported by Provincial and Territorial Ministries of Health, based on laboratory confirmations, sentinel ILI rates and reported outbreaks. Please refer to detailed definitions at the end of the report. Maps from previous weeks, including any retrospective updates, are available in the mapping feature found in the Weekly Influenza Reports.
      Figure 1 - Text Description Laboratory Confirmed Influenza Detections

      In week 14, the percentage of tests positive for influenza continued to decrease from the previous week [from 28% in week 13 to 23% in week 14] (Figure 2). Compared to the previous five seasons, the percent positive (23%) reported in week 14 was above the five year average for that week and exceeded the expected levels (range 11.1%-16.7%). With the late start to the 2015-16 influenza season, these elevated levels are not unexpected.
      Figure 2. Number of positive influenza tests and percentage of tests positive, by type, subtype and report week, Canada, 2015-16

      Figure 2 - Text Description In week 14, there were 1,914 positive influenza tests reported. The number of positive influenza B tests accounted for an increasing proportion of all positive influenza tests reported. Both influenza B and influenza A detections decreased in week 14. This week, influenza B accounted for 41% of all positive tests. To date, 79% of influenza detections have been influenza A and among those subtyped, the vast majority have been influenza A(H1N1) [91% (10510/11511)].
      Figure 3. Cumulative numbers of positive influenza specimens by type/subtype and province, Canada, 2015-16

      Note: Specimens from NT, YT, and NU are sent to reference laboratories in other provinces. Cumulative data includes updates to previous weeks.
      Figure 3 - Text Description To date this season, detailed information on age and type/subtype has been received for 28,818 cases. Children and teenagers (0-19 years of age) accounted for one third of all influenza cases (33%). Children (0-19), young adults (20-44) and middle-aged adults (45-64) accounted for approximately an equal proportion of influenza A(H1N1) cases (28%).
      Table 1 - Footnote 1 Table 1 includes specimens for which demographic information was reported. These represent a subset of all positive influenza cases reported.
      Return to Table 1 - Footnote1referrer
      Table 1 - Footnote 2 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections.
      Return to Table 1 - Footnote2referrer
      Table 1 - Footnote 3 Unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available.
      Return to Table 1 - Footnote3referrer
      Table 1 - Footnote x Suppressed to prevent residual disclosure.
      Return to Table 1 - Footnotexreferrer
      125 15 0 110 124 4287 1674 63 2550 1044 5333 19%
      46 7 <5 Table 1 - Footnotex 138 2302 997 95 1210 1832 4136 14%
      118 30 <5 Table 1 - Footnotex 120 5566 2655 150 2761 1574 7140 25%
      171 37 <5 Table 1 - Footnotex 75 5994 2639 178 3177 763 6757 23%
      175 31 6 138 100 4477 1506 396 2575 974 5452 19%
      635 120 10 505 557 22626 9471 882 12273 6187 28818 100%
      53% 19% 2% 80% 47% 79% 42% 4% 54% 21%
      For data on other respiratory virus detections see the Respiratory Virus Detections in Canada Report on the Public Health Agency of Canada website.
      Influenza-like Illness Consultation Rate

      The national ILI consultation rate decreased from the previous week from 45.2 per 1,000 patient visits in week 13, to 26.8 per 1,000 patient visits in week 14. The highest ILI consultation rate was found in the 0-4 years age group (55.9 per 1,000) and the lowest was found in the ≥65 years age group (5.5 per 1,000) (Figure 4).
      Figure 4. Influenza-like-illness (ILI) consultation rates by age group and week, Canada, 2015-16

      Delays in the reporting of data may cause data to change retrospectively. In BC, AB, and SK, data are compiled by a provincial sentinel surveillance program for reporting to FluWatch. Not all sentinel physicians report every week.
      Figure 4 - Text Description Pharmacy Surveillance

      During week 14, the proportion of prescriptions for antivirals dereaesd to 50.4 antiviral prescriptions per 100,000 total prescriptions, which is lower than the five year historical average for week 14. The proportion of prescriptions for antivirals remains highest among children. In week 14, the proportion reported among children was 102.4 per 100,000 total prescriptions.
      Figure 5. Proportion of prescription sales for influenza antivirals by age group and week, Canada, 2015-16

      Note: Pharmacy sales data are provided to the Public Health Agency of Canada by Rx Canada Inc. and sourced from major retail drug chains representing over 3,000 stores nationwide (excluding Nunavut) in 85% of Health Regions. Data provided include the number of new antiviral prescriptions (for Tamiflu[oseltamivir] and Relenza [zanamivir]) and the total number of new prescriptions dispensed by Province/Territory and age group.
      * The average weekly proportion includes data from April 2011 to March 2015.
      Figure 5 - Text Description Influenza Outbreak Surveillance

      In week 14, 17 new laboratory confirmed influenza outbreaks were reported: 14 in long-term care facilities (LTCF), two in hospitals and one in institutions or community settings. Of the outbreaks with known strains or subtypes, three outbreaks were due to influenza B, one outbreak was due to influenza A(H1N1), two outbreaks were due to influenza A(H3N2) and eight were due to influenza A(UnS). Additionally, three ILI outbreaks were reported schools.
      To date this season, 374 outbreaks have been reported. At week 14 in the 2014-15 season, 1646 outbreaks were reported and in the 2013-14 season,198 outbreaks were reported.
      Figure 6. Overall number of new laboratory-confirmed influenza outbreaksFigure 5 - Footnote1 by report week, Canada, 2015-2016

      Figure 6 - Footnote 1 All provinces and territories except NU report influenza outbreaks in long-term care facilities. All provinces and territories with the exception of NU and QC report outbreaks in hospitals. Outbreaks of influenza or influenza-like-illness in other facilities are reported to FluWatch but reporting varies between jurisdictions. Outbreak definitions are included at the end of the report.
      Return to Figure 5 - Footnote1referrer
      Figure 6 - Text Description Sentinel Pediatric Hospital Influenza Surveillance

      Paediatric Influenza Hospitalizations and Deaths

      Hospitalizations reported by the the Immunization Monitoring Program Active (IMPACT) network continue to decrease (Figure 7). In week 14, 58 hospitalizations were reported. The largest proportion of hospitalizations were in children aged 2-4 years, accounting for 46.5% of the hospitalizations. For the first time this season, more influenza B cases were reported than influenza A cases (31 vs. 27 respectively).
      To date this season, 1,138 laboratory-confirmed influenza-associated pediatric (≤16 years of age) hospitalizations have been reported by the IMPACT network: 853 hospitalized cases (75%) were due to influenza A and 285 cases (25%) were due to influenza B. The greatest proportion of hospitalized cases were in children aged 0-2 years (40 %). To date,190 intensive care unit (ICU) admissions have been reported. Children aged 2 to 4 and 5 to 9 years accounted for 28% and 26% respectively of ICU admissions. A total of 113 ICU cases (59%) reported at least one underlying condition or comorbidity. Eight influenza-associated deaths have been reported.
      Table 2 - Footnote x Suppressed to prevent residual disclosure.
      Return to Table 2 - Footnotexreferrer
      112 32 5 75 21 133 (12%)
      261 73 7 181 59 320 (28%)
      246 78 <5 Table 2 - Footnotex 78 324 (28%)
      177 47 <5 Table 2 - Footnotex 89 266 (23%)
      57 18 <5 Table 2 - Footnotex 38 95 (8%)
      853 248 21 584 285 1138 (100%)
      Figure 7. Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2015-16, paediatric and adult hospitalizations (≤16 years of age, IMPACT; ≥16 years of age, CIRN-SOS)

      Not included in Table 2 and Figure 7 are two IMPACT cases that were due to co-infections of influenza A and B.
      Figure 7 - Text Description Adult Influenza Hospitalizations and Deaths

      In week 14, 36 hospitalizations were reported by the Canadian Immunization Research Network Serious Outcome Surveillance (CIRN-SOS) (Figure 7). The largest proportion of hospitalizations was in adults 65+ years of age (50%) and due to influenza A (75%).
      To date this season, 956 laboratory-confirmed influenza-associated adult (≥16 years of age) hospitalizations have been reported by CIRN-SOS (Table 3). The majority of hospitalized cases were due to influenza A (85%) and the largest reported proportion was among adults ≥65 years of age (49%). One hundred and thirty-seven intensive care unit (ICU) admissions have been reported. A total of 88 ICU cases reported at least one underlying condition or comorbidity. A total of 38 deaths have been reported this season with the majority of deaths reported in adults ≥65 years of age (63%).
      Table 3 - Footnote x Suppressed to prevent residual disclosure.
      Return to Table 3 - Footnotexreferrer
      5 <5 0 <5 <5 6 (1%)
      127 38 <5 Table 3 - Footnotex 28 155 (16%)
      286 84 3 199 30 316 (33%)
      388 96 21 271 84 472 (49%)
      6 0 <5 <5 <5 7 (1%)
      812 225 26 561 144 956
      85% 28% 3% 69% 15% 100%
      Figure 8. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group (≥16 year of age), Canada 2015-16

      Note: The number of hospitalizations reported through CIRN-SOS and IMPACT represents a subset of all influenza-associated adult and paediatric hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
      x - Suppressed to prevent residual disclosure.
      Figure 8 - Text Description Provincial/Territorial Influenza Hospitalizations and Deaths

      In week 14, 311 hospitalizations were reported by participating provinces and territoriesFootnote*. The majority of hospitalizations were due to influenza A (61%), however a marked increase in the proportion of influenza B cases has been noted in week 14. Influenza B accounted for 39% of all influenza hospitalizations in week 14 compared to 22% in week 13. The largest proportion of cases reported in week 14 was in adults 65+ years of age (35%).
      Since the start of the 2015-16 season, 4,371 laboratory-confirmed influenza-associated hospitalizations have been reported. A total of 3,637 hospitalizations (83%) were due to influenza A and 734 (17%) were due to influenza B. Of the 473 ICU admissions reported, 245 (58%) were due to influenza A(H1N1) A total of 193 deaths have been reported; all but 22 were associated with influenza A.
      Overall this season, hospitalizations have been reported more frequently among adults ≥65 years of age. The largest proportion of ICU admissions were reported in adults 45-64 years of age and the highest proportion of fatal cases was reported in adults ≥65 years of age. Pediatric (0-19 years) and young to middle-aged adults (20-44 years) accounted for 42% of all hospitalizations and 15% of all deaths reported to date this season.
      Figure 9. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada 2015-16

      Figure 9 - Text Description Footnote * Note: Influenza-associated hospitalizations are not reported to PHAC by the following Provinces and Territory: BC, NU, and QC. Only hospitalizations that require intensive medical care are reported by SK. ICU admissions are not distinguished among hospital admissions reported from ON. Data may also include cases reported by the IMPACT networks. The number of new influenza-associated hospitalizations and deaths reported for the current week may include cases from ON that occurred in previous weeks, as a result of retrospective updates to the cumulative total. It is important to note that the hospitalization or death does not have to be attributable to influenza, a positive laboratory test is sufficient for reporting.
      Return to footnote*referrer
      Footnote * Includes three hospitalizations for which age is unknown.
      Return to footnote1referrer
      See additional data on Reported Influenza Hospitalizations and Deaths in Canada: 2011-12 to 2015-16 on the Public Health Agency of Canada website.
      Influenza Strain Characterizations

      During the 2015-16 influenza season, the National Microbiology Laboratory (NML) has characterized 1580 influenza viruses [179 A(H3N2), 889 A(H1N1) and 512 influenza B].
      Influenza A (H3N2): When tested by hemagglutination inhibition (HI) assays, 42 A(H3N2) viruses were antigenically characterized as A/Switzerland/9715293/2013-like using antiserum raised against cell-propagated A/Switzerland/9715293/2013.
      Sequence analysis was done on 137 A(H3N2) viruses. All viruses belonged to a genetic group for which most viruses were antigenically related to A/Switzerland/9715293/2013. A/Switzerland/9715293/2013 is the A(H3N2) component of the 2015-16 Northern Hemisphere's vaccine.
      Influenza A (H1N1): All of the 889 A(H1N1) viruses characterized were antigenically similar to A/California/7/2009, the A(H1N1) component of the 2015-16 influenza vaccine.
      Influenza B: A total of 125 influenza B viruses characterized were antigenically similar to the vaccine strain B/Phuket/3073/2013. A total of 387 influenza B viruses were characterized as B/Brisbane/60/2008-like, one of the influenza B components of the 2015-16 Northern Hemisphere quadrivalent influenza vaccine.
      The recommended components for the 2015-2016 northern hemisphere trivalent influenza vaccine include: an A/California/7/2009(H1N1)pdm09-like virus, an A/Switzerland/9715293/2013(H3N2)-like virus, and a B/Phuket/3073/2013 -like virus (Yamagata lineage). For quadrivalent vaccines, the addition of a B/Brisbane/60/2008-like virus (Victoria lineage) is recommended.
      The NML receives a proportion of the influenza positive specimens from provincial laboratories for strain characterization and antiviral resistance testing. Characterization data reflect the results of haemagglutination inhibition testing compared to the reference influenza strains recommended by WHO.
      .../



      "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerable citizens in our society, a life free of violence and fear."
      -Nelson Mandela

      Comment


      • #18
        FluWatch report: April 10 to April 16, 2016 (week 15)

        Overall Summary

        • Influenza activity peaked nationally in the second week of March; however, lower but sustained activity continues to be reported throughout the country.
        • Many regions across Canada are reporting a greater number of influenza B detections; however, in British Columbia and the Atlantic Region, detections remain predominantly influenza A.
        • Hospitalizations, ICU admissions and deaths among the pediatric population, while declining, remain above expected levels based on the past several influenza seasons.
        • Despite higher pediatric hospitalizations reported, the pediatric population accounts for the smallest proportion of all deaths reported.
        • For more information on the flu, see our Flu(influenza) web page.

        Download the alternative format
        (PDF format, 908 KB, 9 pages)
        Organization: Public Health Agency of Canada
        Date published: 2016-04-22

        Related Topics



        Are you a primary health care practitioner (General Practitioner, Nurse Practitioner or Registered Nurse) interested in becoming a FluWatch sentinel for the 2015-16 influenza season? Contact us at FluWatch@phac-aspc.gc.ca


        On this page

        Influenza/Influenza-like Illness Activity (geographic spread)

        Influenza activity continues to be reported in the majority of regions in Canada. Localized activity was reported in a total of 14 regions across seven provinces. Sporadic activity levels were reported in 31 regions.
        Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, week 15




        Note: Influenza/ILI activity levels, as represented on this map, are assigned and reported by Provincial and Territorial Ministries of Health, based on laboratory confirmations, sentinel ILI rates and reported outbreaks. Please refer to detailed definitions at the end of the report. Maps from previous weeks, including any retrospective updates, are available in the mapping feature found in the Weekly Influenza Reports.
        Figure 1 - Text Description Laboratory Confirmed Influenza Detections

        In week 15, the percentage of tests positive for influenza continued to decrease from the previous week [from 23% in week 14 to 21% in week 15] (Figure 2). Compared to the previous five seasons, the percent positive (21%) reported in week 15 was above the five year average for that week and exceeded the expected levels (range 11.7%-16.9%). With the late start to the 2015-16 influenza season, these elevated levels are not unexpected.
        Figure 2. Number of positive influenza tests and percentage of tests positive, by type, subtype and report week, Canada, 2015-16

        Figure 2 - Text Description Nationally in week 15, there were 1,522 positive influenza tests reported. The number of influenza A and influenza B detections were roughly equal in week 15. Many of regions across Canada reported more influenza B detections than influenza A; however, in British Columbia and the Atlantic Region, detections remain predominantly influenza A. To date, 78% of influenza detections have been influenza A and among those subtyped, the vast majority have been influenza A(H1N1) [86% (10715/12443)].
        Figure 3. Cumulative numbers of positive influenza specimens by type/subtype and province, Canada, 2015-16

        Note: Specimens from NT, YT, and NU are sent to reference laboratories in other provinces. Cumulative data includes updates to previous weeks.
        Figure 3 - Text Description In week 15, individuals under the age of 44 accounted for 74% of influenza B detections. To date this season, detailed information on age and type/subtype has been received for 30,052 cases. Children and teenagers (0-19) accounted for 47% of influenza B cases and approximately one third of all influenza cases. Children and teenagers (0-19), young adults (20-44) and middle-aged adults (45-64) accounted for approximately an equal proportion of influenza A(H1N1) cases (28%).
        Table 1 - Footnote 1 Table 1 includes specimens for which demographic information was reported. These represent a subset of all positive influenza cases reported.
        Return to Table 1 - Footnote1referrer
        Table 1 - Footnote 2 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections.
        Return to Table 1 - Footnote2referrer
        Table 1 - Footnote 3 Unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available.
        Return to Table 1 - Footnote3referrer
        Table 1 - Footnote x Suppressed to prevent residual disclosure.
        Return to Table 1 - Footnotexreferrer
        80 6 <5 Table 1 - Footnotex 118 4396 1690 67 2639 1179 5577 19%
        37 <5 0 Table 1 - Footnotex 160 2346 1011 97 1238 2043 4391 15%
        74 17 0 57 110 5669 2699 151 2819 1726 7395 25%
        121 28 <5 Table 1 - Footnotex 47 6165 2709 181 3275 827 6992 23%
        101 17 7 77 91 4608 1558 410 2640 1088 5697 19%
        413 72 11 330 526 23184 9667 906 12611 6863 30052 100%
        44% 17% 3% 80% 56% 77% 42% 4% 54% 23%
        For data on other respiratory virus detections see the Respiratory Virus Detections in Canada Report on the Public Health Agency of Canada website.
        Influenza-like Illness Consultation Rate

        The national ILI consultation rate increased from the previous week from 26.1 per 1,000 patient visits in week 14, to 56.4 per 1,000 patient visits in week 15. The highest ILI consultation rate was found in the 5-19 years age group (107.7 per 1,000) and the lowest was found in the ≥65 years age group (14.2 per 1,000) (Figure 4).
        Figure 4. Influenza-like-illness (ILI) consultation rates by age group and week, Canada, 2015-16

        Delays in the reporting of data may cause data to change retrospectively. In BC, AB, and SK, data are compiled by a provincial sentinel surveillance program for reporting to FluWatch. Not all sentinel physicians report every week.
        Figure 4 - Text Description Pharmacy Surveillance

        During week 15, the proportion of prescriptions for antivirals remained similar to the previous week at 50.6 antiviral prescriptions per 100,000 total prescriptions, which is lower than the five year historical average for week 15. The proportion of prescriptions for antivirals remains highest among children. In week 15, the proportion reported among children was 100.1 per 100,000 total prescriptions.
        Figure 5. Proportion of prescription sales for influenza antivirals by age group and week, Canada, 2015-16

        Note: Pharmacy sales data are provided to the Public Health Agency of Canada by Rx Canada Inc. and sourced from major retail drug chains representing over 3,000 stores nationwide (excluding Nunavut) in 85% of Health Regions. Data provided include the number of new antiviral prescriptions (for Tamiflu[oseltamivir] and Relenza [zanamivir]) and the total number of new prescriptions dispensed by Province/Territory and age group.
        * The average weekly proportion includes data from April 2011 to March 2015.
        Figure 5 - Text Description Influenza Outbreak Surveillance

        In week 15, 12 new laboratory confirmed influenza outbreaks were reported: 11 in long-term care facilities (LTCF) and one in a hospital. Of the seven outbreaks with known strains or subtypes, four outbreaks were due to influenza B (three in LTCFs and one in a hospital), one outbreak each was due to influenza A(H1N1) and influenza A(H3N2) (both in LTCFs), and one outbreak in a LTCF was due to influenza A(UnS). Additionally, one ILI outbreak was reported in a school.
        To date this season, 387 outbreaks have been reported. At week 15 in the 2014-15 season, 1,586 outbreaks were reported and in the 2013-14 season, 210 outbreaks were reported.
        Figure 6. Overall number of new laboratory-confirmed influenza outbreaksFigure 5 - Footnote1 by report week, Canada, 2015-2016

        Figure 6 - Footnote 1 All provinces and territories except NU report influenza outbreaks in long-term care facilities. All provinces and territories with the exception of NU and QC report outbreaks in hospitals. Outbreaks of influenza or influenza-like-illness in other facilities are reported to FluWatch but reporting varies between jurisdictions. Outbreak definitions are included at the end of the report.
        Return to Figure 5 - Footnote1referrer
        Figure 6 - Text Description Sentinel Pediatric Hospital Influenza Surveillance

        Paediatric Influenza Hospitalizations and Deaths

        In week 15, 63 laboratory-confirmed influenza-associated pediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network (Figure 7). The largest proportion of hospitalizations were in children aged 5-9 years, accounting for 33% of the hospitalizations. Similar to the previous week, more influenza B cases were reported than influenza A cases (41 vs. 22 respectively).
        To date this season, 1,207 hospitalizations have been reported by the IMPACT network: 874 hospitalized cases (72%) were due to influenza A and 333 cases (28%) were due to influenza B. The greatest proportion of hospitalized cases were in children aged 0-2 years (40%). To date,192 intensive care unit (ICU) admissions have been reported. Children aged 2 to 4 and 5 to 9 years accounted for 28% and 26% respectively of ICU admissions. A total of 122 ICU cases (64%) reported at least one underlying condition or comorbidity. Eight influenza-associated deaths have been reported.
        Table 2 - Footnote x Suppressed to prevent residual disclosure.
        Return to Table 2 - Footnotexreferrer
        116 32 5 79 26 142 (12%)
        270 73 7 190 66 336 (28%)
        251 79 <5 Table 2 - Footnotex 93 344 (29%)
        179 47 <5 Table 2 - Footnotex 106 285 (24%)
        58 18 <5 Table 2 - Footnotex 42 100 (8%)
        874 249 21 604 333 1207 (100%)
        Figure 7. Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2015-16, paediatric and adult hospitalizations (≤16 years of age, IMPACT; ≥16 years of age, CIRN-SOS)

        Not included in Table 2 and Figure 7 are two IMPACT cases that were due to co-infections of influenza A and B.
        Figure 7 - Text Description Adult Influenza Hospitalizations and Deaths

        In week 15, 39 laboratory-confirmed influenza-associated adult (≥16 years of age) hospitalizations were reported by the Canadian Immunization Research Network Serious Outcome Surveillance (CIRN-SOS) (Figure 7). The largest proportion of hospitalizations was in adults 65+ years of age (54%) and due to influenza A (62%). In recent weeks, the weekly number of hospitalizations reported by CIRN has been decreasing and an increasing proportion of hospitalizations have been due to influenza B.
        To date this season, 1,077 hospitalizations have been reported by CIRN-SOS (Table 3). The majority of hospitalized cases were due to influenza A (83%) and the largest reported proportion was among adults ≥65 years of age (50%). One hundred and sixty-five intensive care unit (ICU) admissions have been reported. A total of 112 ICU cases reported at least one underlying condition or comorbidity. A total of 45 deaths have been reported this season with the majority of deaths reported in adults ≥65 years of age (64%).
        Table 3 - Footnote x Suppressed to prevent residual disclosure.
        Return to Table 3 - Footnotexreferrer
        Table 3 - Footnotex <5 0 <5 <5 7 (1%)
        140 45 <5 Table 3 - Footnotex 36 176 (16%)
        312 94 <5 Table 3 - Footnotex 39 351 (33%)
        434 119 23 292 103 537 (50%)
        <5 0 0 <5 <5 6 (1%)
        895 264 27 604 182 1077
        83% 29% 3% 67% 17% 100%
        Figure 8. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group (≥16 year of age), Canada 2015-16

        Note: The number of hospitalizations reported through CIRN-SOS and IMPACT represents a subset of all influenza-associated adult and paediatric hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
        x - Suppressed to prevent residual disclosure.
        Figure 8 - Text Description Provincial/Territorial Influenza Hospitalizations and Deaths

        In week 15, 182 hospitalizations were reported by participating provinces and territoriesFootnote*. The majority of reported hospitalizations continue to be due to influenza A, accounting for 63% of hospitalizations reported in week 15. The largest proportion of cases reported in week 15 was in adults 65+ years of age (43%).
        Since the start of the 2015-16 season, 4,606 laboratory-confirmed influenza-associated hospitalizations have been reported. A total of 3,802 hospitalizations (83%) were due to influenza A and 804 (17%) were due to influenza B. Of the 486 ICU admissions reported, 258 (53%) were due to influenza A(H1N1). A total of 193 deaths have been reported; all but 24 were associated with influenza A.
        Overall this season, hospitalizations have been reported more frequently among adults ≥65 years of age. The largest proportion of ICU admissions was reported in adults 45-64 years of age and the highest proportion of fatal cases was reported in adults ≥65 years of age. Pediatric (0-19 years) and young to middle-aged adults (20-44 years) accounted for 42% of all hospitalizations and 14% of all deaths reported to date this season. There have been more pediatric hospitalizations reported to date compared to the year-end totals in each of the previous four influenza seasons.
        Figure 9. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada 2015-16

        Figure 9 - Text Description Footnote * Note: Influenza-associated hospitalizations are not reported to PHAC by the following Provinces and Territory: BC, NU, and QC. Only hospitalizations that require intensive medical care are reported by SK. ICU admissions are not distinguished among hospital admissions reported from ON. Data may also include cases reported by the IMPACT networks. The number of new influenza-associated hospitalizations and deaths reported for the current week may include cases from ON that occurred in previous weeks, as a result of retrospective updates to the cumulative total. It is important to note that the hospitalization or death does not have to be attributable to influenza, a positive laboratory test is sufficient for reporting.
        Return to footnote*referrer
        Footnote * Includes three hospitalizations for which age is unknown.
        Return to footnote1referrer
        See additional data on Reported Influenza Hospitalizations and Deaths in Canada: 2011-12 to 2015-16 on the Public Health Agency of Canada website.
        Influenza Strain Characterizations

        During the 2015-16 influenza season, the National Microbiology Laboratory (NML) has characterized 1,901 influenza viruses [189 A(H3N2), 1,099 A(H1N1) and 613 influenza B].
        Influenza A (H3N2): When tested by hemagglutination inhibition (HI) assays, 48 A(H3N2) viruses were antigenically characterized as A/Switzerland/9715293/2013-like using antiserum raised against cell-propagated A/Switzerland/9715293/2013.
        Sequence analysis was done on 141 A(H3N2) viruses. All viruses belonged to a genetic group for which most viruses were antigenically related to A/Switzerland/9715293/2013. A/Switzerland/9715293/2013 is the A(H3N2) component of the 2015-16 Northern Hemisphere's vaccine.
        Influenza A (H1N1): All of the 1,099 A(H1N1) viruses characterized were antigenically similar to A/California/7/2009, the A(H1N1) component of the 2015-16 influenza vaccine.
        Influenza B: A total of 142 influenza B viruses characterized were antigenically similar to the vaccine strain B/Phuket/3073/2013. A total of 471 influenza B viruses were characterized as B/Brisbane/60/2008-like, one of the influenza B components of the 2015-16 Northern Hemisphere quadrivalent influenza vaccine.
        The recommended components for the 2015-2016 northern hemisphere trivalent influenza vaccine include: an A/California/7/2009(H1N1)pdm09-like virus, an A/Switzerland/9715293/2013(H3N2)-like virus, and a B/Phuket/3073/2013 -like virus (Yamagata lineage). For quadrivalent vaccines, the addition of a B/Brisbane/60/2008-like virus (Victoria lineage) is recommended.
        The NML receives a proportion of the influenza positive specimens from provincial laboratories for strain characterization and antiviral resistance testing. Characterization data reflect the results of haemagglutination inhibition testing compared to the reference influenza strains recommended by WHO.
        .../



        "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerable citizens in our society, a life free of violence and fear."
        -Nelson Mandela

        Comment


        • #19
          FluWatch report: April 17 to April 23, 2016 (week 16)

          Overall Summary

          • In week 16, all influenza indicators remained similar to, or declined from the previous week.
          • Elevated influenza activity was mostly reported in the Ontario, Quebec and Atlantic provinces.
          • Many regions across Canada are reporting a greater proportion of influenza B detections. This increase in influenza B is expected as influenza B often shows up later in the flu season.
          • Influenza B continues to account for a increasing proportion of hospitalizations among children and adults.
          • Hospitalizations, ICU admissions and deaths among the pediatric population, while declining, continue to remain above expected levels based on the past several influenza seasons.
          • For more information on the flu, see our Flu(influenza) web page.

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          Organization: Public Health Agency of Canada
          Date published: 2016-04-29

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          Are you a primary health care practitioner (General Practitioner, Nurse Practitioner or Registered Nurse) interested in becoming a FluWatch sentinel for the 2015-16 influenza season? Contact us at FluWatch@phac-aspc.gc.ca


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          Influenza/Influenza-like Illness Activity (geographic spread)

          Influenza activity continues to be reported in the majority of regions in Canada; however, the number of regions reporting influenza activity decreased in week 16. Localized activity was reported in a total of 13 regions across five provinces. Sporadic activity levels were reported in 30 regions across all provinces and territories.
          Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, week 16




          Note: Influenza/ILI activity levels, as represented on this map, are assigned and reported by Provincial and Territorial Ministries of Health, based on laboratory confirmations, sentinel ILI rates and reported outbreaks. Please refer to detailed definitions at the end of the report. Maps from previous weeks, including any retrospective updates, are available in the mapping feature found in the Weekly Influenza Reports.
          Figure 1 - Text Description Laboratory Confirmed Influenza Detections

          In week 16, the percentage of tests positive for influenza continued to decrease from the previous week [from 21% in week 15 to 19% in week 16], driven by the decline in influenza A. Compared to the previous five seasons, the percent positive (19%) reported in week 16 was above the five year average for that week and exceeded the expected levels (range 10.1%-16.2%). With the late start to the 2015-16 influenza season, these elevated levels are not unexpected.
          Figure 2. Number of positive influenza tests and percentage of tests positive, by type, subtype and report week, Canada, 2015-16

          Figure 2 - Text Description Nationally in week 16, there were 1,140 positive influenza tests reported. Influenza B continues to account for an increasing proportion of influenza detections accounting for 64% of detections in week 16. Detections remain predominantly influenza A in British Columbia and the Atlantic Region. To date, 76% of influenza detections have been influenza A and among those subtyped, the vast majority have been influenza A(H1N1) [92% (10866/11855)].
          Figure 3. Cumulative numbers of positive influenza specimens by type/subtype and province, Canada, 2015-16

          Note: Specimens from NT, YT, and NU are sent to reference laboratories in other provinces. Cumulative data includes updates to previous weeks.
          Figure 3 - Text Description In week 16, individuals under the age of 44 accounted for 69% of influenza B detections.
          To date this season, detailed information on age and type/subtype has been received for 31,063 cases. Children and teenagers (0-19) accounted for 47% of influenza B cases and approximately one third of all influenza cases. Children and teenagers (0-19), young adults (20-44) and middle-aged adults (45-64) accounted for approximately an equal proportion of influenza A(H1N1) cases (28%).
          Table 1 - Footnote 1 Table 1 includes specimens for which demographic information was reported. These represent a subset of all positive influenza cases reported.
          Return to Table 1 - Footnote1referrer
          Table 1 - Footnote 2 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections.
          Return to Table 1 - Footnote2referrer
          Table 1 - Footnote 3 Unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available.
          Return to Table 1 - Footnote3referrer
          Table 1 - Footnote x Suppressed to prevent residual disclosure.
          Return to Table 1 - Footnotexreferrer
          41 <5 <5 34 112 4450 1698 69 2683 1309 5761 19%
          14 <5 Table 1 - Footnotex 12 153 2373 1017 99 1257 2231 4606 15%
          51 10 0 41 114 5735 2717 154 2864 1876 7611 25%
          65 13 <5 Table 1 - Footnotex 66 6255 2739 185 3331 905 7160 23%
          82 18 <5 Table 1 - Footnotex 105 4712 1587 417 2708 1212 5925 19%
          253 47 <5 202 550 23525 9758 924 12843 7533 31063 100%
          32% 19% 2% 80% 68% 76% 41% 4% 55% 24%
          For data on other respiratory virus detections see the Respiratory Virus Detections in Canada Report on the Public Health Agency of Canada website.
          Influenza-like Illness Consultation Rate

          The national ILI consultation rate decreased from the previous week from 56.4 per 1,000 patient visits in week 15, to 36.1 per 1,000 patient visits in week 16. The highest ILI consultation rate was found in the 0-4 years age group (104.4 per 1,000) and the lowest was found in the ≥65 years age group (18.8 per 1,000) (Figure 4).
          Figure 4. Influenza-like-illness (ILI) consultation rates by age group and week, Canada, 2015-16

          Delays in the reporting of data may cause data to change retrospectively. In BC, AB, and SK, data are compiled by a provincial sentinel surveillance program for reporting to FluWatch. Not all sentinel physicians report every week.
          Figure 4 - Text Description Pharmacy Surveillance

          During week 16, the proportion of prescriptions for antivirals decreased from the previous week to 27.7 antiviral prescriptions per 100,000 total prescriptions, which is lower than the five year historical average for week 16. The proportion of prescriptions for antivirals remains highest among children. In week 16, the proportion reported among children was 71.5 per 100,000 total prescriptions.
          Figure 5. Proportion of prescription sales for influenza antivirals by age group and week, Canada, 2015-16

          Note: Pharmacy sales data are provided to the Public Health Agency of Canada by Rx Canada Inc. and sourced from major retail drug chains representing over 3,000 stores nationwide (excluding Nunavut) in 85% of Health Regions. Data provided include the number of new antiviral prescriptions (for Tamiflu[oseltamivir] and Relenza [zanamivir]) and the total number of new prescriptions dispensed by Province/Territory and age group.
          * The average weekly proportion includes data from April 2011 to March 2015.
          Figure 5 - Text Description Influenza Outbreak Surveillance

          In week 16, 13 new laboratory confirmed influenza outbreaks were reported: nine in long-term care facilities (LTCF). three in hospitals and one in an institution or community setting. Of the outbreaks with known strains or subtypes, all three outbreaks were due to influenza B (two in LTCFs and one in an institution or community setting). Additionally, one ILI outbreak was reported in a school.
          To date this season, 401 outbreaks have been reported. At week 16 in the 2014-15 season, 1,607 outbreaks were reported and in the 2013-14 season, 218 outbreaks were reported.
          Figure 6. Overall number of new laboratory-confirmed influenza outbreaksFigure 5 - Footnote1 by report week, Canada, 2015-2016

          Figure 6 - Footnote 1 All provinces and territories except NU report influenza outbreaks in long-term care facilities. All provinces and territories with the exception of NU and QC report outbreaks in hospitals. Outbreaks of influenza or influenza-like-illness in other facilities are reported to FluWatch but reporting varies between jurisdictions. Outbreak definitions are included at the end of the report.
          Return to Figure 5 - Footnote1referrer
          Figure 6 - Text Description Sentinel Pediatric Hospital Influenza Surveillance

          Paediatric Influenza Hospitalizations and Deaths

          In week 16, 33 laboratory-confirmed influenza-associated pediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network (Figure 7). The largest proportion of hospitalizations were in children aged 5-9 years, accounting for 30% of the hospitalizations. Similar to the trend of increased laboratory detections of influenza B, 82% of pediatric hospitalizations reported in week 16 were due to influenza B.
          To date this season, 1,233 hospitalizations have been reported by the IMPACT network: 878 hospitalized cases (71%) were due to influenza A and 355 cases (29%) were due to influenza B. This season's count of pediatric hospitalizations is nearly double that reported up to week 16 (667) in the 2015-16 season. The current year total number of cases also exceeds the total number of cases reported in the past five seasons.
          A total of 193 intensive care unit (ICU) admissions have been reported. Children aged 2 to 4 and 5 to 9 years accounted for 29% and 26% respectively of ICU admissions. A total of 128 ICU cases (66%) reported at least one underlying condition or comorbidity. Eight influenza-associated deaths have been reported.
          Table 2 - Footnote x Suppressed to prevent residual disclosure.
          Return to Table 2 - Footnotexreferrer
          118 32 5 81 29 147 (12%)
          271 73 7 191 71 342 (28%)
          250 79 <5 Table 2 - Footnotex 96 346 (28%)
          181 47 <5 Table 2 - Footnotex 115 296 (24%)
          58 18 <5 Table 2 - Footnotex 44 102 (8%)
          878 249 21 608 355 1233 (100%)
          Figure 7. Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2015-16, paediatric and adult hospitalizations (≤16 years of age, IMPACT; ≥16 years of age, CIRN-SOS)

          Not included in Table 2 and Figure 7 are two IMPACT cases that were due to co-infections of influenza A and B.
          Figure 7 - Text Description Adult Influenza Hospitalizations and Deaths

          In week 16, 28 laboratory-confirmed influenza-associated adult (≥16 years of age) hospitalizations were reported by the Canadian Immunization Research Network Serious Outcome Surveillance (CIRN-SOS) (Figure 7). The largest proportion of hospitalizations was in adults 65+ years of age (53%) and due to influenza A (53%). In recent weeks, the weekly number of hospitalizations reported by CIRN has been decreasing and an increasing proportion of hospitalizations have been due to influenza B.
          To date this season, 1,108 hospitalizations have been reported by CIRN-SOS (Table 3). The majority of hospitalized cases were due to influenza A (82%) and the largest reported proportion was among adults ≥65 years of age (50%). One hundred and seventy-four intensive care unit (ICU) admissions have been reported of which 118 cases reported at least one underlying condition or comorbidity. A total of 48 deaths have been reported this season with the majority of deaths reported in adults ≥65 years of age (67%).
          Table 3 - Footnote x Suppressed to prevent residual disclosure.
          Return to Table 3 - Footnotexreferrer
          Table 3 - Footnotex <5 0 <5 <5 7 (1%)
          140 48 <5 Table 3 - Footnotex 39 179 (16%)
          321 97 <5 Table 3 - Footnotex 40 361 (33%)
          443 123 23 297 113 556 (50%)
          <5 0 0 <5 <5 5 (%)
          912 273 27 612 196 1108
          82% 30% 3% 67% 18% 100%
          Figure 8. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group (≥16 year of age), Canada 2015-16

          Note: The number of hospitalizations reported through CIRN-SOS and IMPACT represents a subset of all influenza-associated adult and paediatric hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
          x - Suppressed to prevent residual disclosure.
          Figure 8 - Text Description Provincial/Territorial Influenza Hospitalizations and Deaths

          In week 16, 129 hospitalizations were reported by participating provinces and territoriesFootnote*. Influenza B accounted for the greatest proportion of hospitalizations, accounting for 55% of hospitalizations reported in week 16. The largest proportion of cases reported was in adults 65+ years of age (37%). Among hospitalizations for influenza B, children represented 35% of cases.
          Since the start of the 2015-16 season, 4,840 laboratory-confirmed influenza-associated hospitalizations have been reported. A total of 3,929 hospitalizations (81%) were due to influenza A and 911 (19%) were due to influenza B. Of the 510 ICU admissions reported, 267 (52%) were due to influenza A(H1N1). A total of 229 deaths have been reported; all but 30 were associated with influenza A.
          Overall this season, hospitalizations have been reported more frequently among adults ≥65 years of age. The largest proportion of ICU admissions was reported in adults 45-64 years of age and the highest proportion of fatal cases was reported in adults ≥65 years of age. Pediatric (0-19 years) and young to middle-aged adults (20-44 years) accounted for 42% of all hospitalizations and 14% of all deaths reported to date this season. Similar to findings from the IMPACT network, there have been more pediatric hospitalizations reported to date compared to the year-end totals in each of the previous four influenza seasons.
          Figure 9. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada 2015-16

          Figure 9 - Text Description Footnote * Note: Influenza-associated hospitalizations are not reported to PHAC by the following Provinces and Territory: BC, NU, and QC. Only hospitalizations that require intensive medical care are reported by SK. ICU admissions are not distinguished among hospital admissions reported from ON. Data may also include cases reported by the IMPACT networks. The number of new influenza-associated hospitalizations and deaths reported for the current week may include cases from ON that occurred in previous weeks, as a result of retrospective updates to the cumulative total. It is important to note that the hospitalization or death does not have to be attributable to influenza, a positive laboratory test is sufficient for reporting.
          Return to footnote*referrer
          Footnote * Includes three hospitalizations for which age is unknown.
          Return to footnote1referrer
          See additional data on Reported Influenza Hospitalizations and Deaths in Canada: 2011-12 to 2015-16 on the Public Health Agency of Canada website.
          Influenza Strain Characterizations

          During the 2015-16 influenza season, the National Microbiology Laboratory (NML) has characterized 2,117 influenza viruses [194 A(H3N2), 1,188 A(H1N1) and 735 influenza B].
          Influenza A (H3N2): When tested by hemagglutination inhibition (HI) assays, 50 A(H3N2) viruses were antigenically characterized as A/Switzerland/9715293/2013-like using antiserum raised against cell-propagated A/Switzerland/9715293/2013.
          Sequence analysis was done on 144 A(H3N2) viruses. All viruses belonged to a genetic group for which most viruses were antigenically related to A/Switzerland/9715293/2013. A/Switzerland/9715293/2013 is the A(H3N2) component of the 2015-16 Northern Hemisphere's vaccine.
          Influenza A (H1N1): All of the 1,188 A(H1N1) viruses characterized were antigenically similar to A/California/7/2009, the A(H1N1) component of the 2015-16 influenza vaccine.
          Influenza B: A total of 154 influenza B viruses characterized were antigenically similar to the vaccine strain B/Phuket/3073/2013. A total of 581 influenza B viruses were characterized as B/Brisbane/60/2008-like, one of the influenza B components of the 2015-16 Northern Hemisphere quadrivalent influenza vaccine.
          The recommended components for the 2015-2016 northern hemisphere trivalent influenza vaccine include: an A/California/7/2009(H1N1)pdm09-like virus, an A/Switzerland/9715293/2013(H3N2)-like virus, and a B/Phuket/3073/2013 -like virus (Yamagata lineage). For quadrivalent vaccines, the addition of a B/Brisbane/60/2008-like virus (Victoria lineage) is recommended.
          The NML receives a proportion of the influenza positive specimens from provincial laboratories for strain characterization and antiviral resistance testing. Characterization data reflect the results of haemagglutination inhibition testing compared to the reference influenza strains recommended by WHO.
          ../


          "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerable citizens in our society, a life free of violence and fear."
          -Nelson Mandela

          Comment


          • #20
            FluWatch report: April 24 to April 30, 2016 (week 17)

            Overall Summary

            • In week 17, all influenza indicators declined from the previous week.
            • Elevated influenza B activity persisited in many regions across Canada: influenza B accounted for the majority of influenza detections in week 17. Additionally, all outbreaks reported this week were due to Influenza B. This increase in influenza B is expected as influenza B often shows up later in the flu season.
            • Hospitalizations, ICU admissions and deaths among the pediatric population, while declining, continue to remain above expected levels based on the past several influenza seasons.
            • For more information on the flu, see our Flu(influenza) web page.
            • The current FluWatch report is the last weekly report for the 2015-2016 season. During the summer, monthly reports will be published starting on May 27, 2016. We will continue to monitor influenza and other respiratory infections via the RVDSS report, published every Thursday.

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            Organization: Public Health Agency of Canada
            Date published: 2016-05-06

            Related Topics



            Are you a primary health care practitioner (General Practitioner, Nurse Practitioner or Registered Nurse) interested in becoming a FluWatch sentinel for the 2015-16 influenza season? Contact us at FluWatch@phac-aspc.gc.ca


            On this page

            Influenza/Influenza-like Illness Activity (geographic spread)

            Influenza activity continues to be reported in the majority of regions in Canada; however, the number of regions reporting influenza activity decreased in week 17. Localized activity was reported in a total of 12 regions across six provinces. Sporadic activity levels were reported in 28 regions across all provinces and territories. A total of 10 regions reported no influenza activity in week 17.
            Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, week 17




            Note: Influenza/ILI activity levels, as represented on this map, are assigned and reported by Provincial and Territorial Ministries of Health, based on laboratory confirmations, sentinel ILI rates and reported outbreaks. Please refer to detailed definitions at the end of the report. Maps from previous weeks, including any retrospective updates, are available in the mapping feature found in the Weekly Influenza Reports.
            Figure 1 - Text Description Laboratory Confirmed Influenza Detections

            In week 17, the percentage of tests positive for influenza continued to decrease from the previous week [from 18% in week 16 to 17% in week 17], driven by the decline in influenza A. Compared to the previous five seasons, the percent positive (17%) reported in week 17 was above the five year average for that week and exceeded the range of expected levels (9.8%-14.0%). With the late start to the 2015-16 influenza season, these elevated levels are not unexpected.
            Figure 2. Number of positive influenza tests and percentage of tests positive, by type, subtype and report week, Canada, 2015-16

            Figure 2 - Text Description Nationally in week 17, there were 881 positive influenza tests reported. Influenza B continues to account for an increasing proportion of influenza detections accounting for 70% of detections in week 17. Detections remain predominantly influenza A in British Columbia and the Atlantic Region. To date, 75% of influenza detections have been influenza A and among those subtyped, the vast majority have been influenza A(H1N1) [91% (10933/11990)].
            Figure 3. Cumulative numbers of positive influenza specimens by type/subtype and province, Canada, 2015-16

            Note: Specimens from NT, YT, and NU are sent to reference laboratories in other provinces. Cumulative data includes updates to previous weeks.
            Figure 3 - Text Description In week 17, individuals under the age of 45 accounted for 64% of influenza B detections.
            To date this season, detailed information on age and type/subtype has been received for 31,858 cases. Children and teenagers (0-19) accounted for 47% of influenza B cases and approximately one third of all influenza cases. Children and teenagers (0-19), young adults (20-44) and middle-aged adults (45-64) accounted for approximately an equal proportion of influenza A(H1N1) cases (28%).
            Table 1 - Footnote 1 Table 1 includes specimens for which demographic information was reported. These represent a subset of all positive influenza cases reported.
            Return to Table 1 - Footnote1referrer
            Table 1 - Footnote 2 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections.
            Return to Table 1 - Footnote2referrer
            Table 1 - Footnote 3 Unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available.
            Return to Table 1 - Footnote3referrer
            Table 1 - Footnote x Suppressed to prevent residual disclosure.
            Return to Table 1 - Footnotexreferrer
            23 <5 Table 1 - Footnotex 20 106 4491 1708 72 2711 1432 5925 19%
            12 <5 <5 10 117 2393 1026 100 1267 2371 4766 15%
            19 6 <5 12 82 5769 2750 155 2864 1986 7755 24%
            39 7 <5 Table 1 - Footnotex 48 6312 2772 190 3350 970 7282 23%
            51 6 <5 Table 1 - Footnotex 120 4778 1612 420 2746 1351 6130 19%
            144 23 6 115 473 23743 9868 937 12938 8110 31858 100%
            23% 16% 4% 80% 77% 75% 42% 4% 54% 25%
            For data on other respiratory virus detections see the Respiratory Virus Detections in Canada Report on the Public Health Agency of Canada website.
            Influenza-like Illness Consultation Rate

            The national ILI consultation rate decreased from the previous week from 36.1 per 1,000 patient visits in week 16, to 31.1 per 1,000 patient visits in week 17. The highest ILI consultation rate was found in the 5-19 years age group (53.8 per 1,000) and the lowest was found in the 20-64 years age group (24.4 per 1,000) (Figure 4).
            Figure 4. Influenza-like-illness (ILI) consultation rates by age group and week, Canada, 2015-16

            Delays in the reporting of data may cause data to change retrospectively. In BC, AB, and SK, data are compiled by a provincial sentinel surveillance program for reporting to FluWatch. Not all sentinel physicians report every week.
            Figure 4 - Text Description Pharmacy Surveillance

            During week 17, the proportion of prescriptions for antivirals decreased from the previous week to 21.2 antiviral prescriptions per 100,000 total prescriptions, which is lower than the five year historical average for week 17. The proportion of prescriptions for antivirals remains highest among children. In week 17, the proportion reported among children was 62.5 per 100,000 total prescriptions.
            Figure 5. Proportion of prescription sales for influenza antivirals by age group and week, Canada, 2015-16

            Note: Pharmacy sales data are provided to the Public Health Agency of Canada by Rx Canada Inc. and sourced from major retail drug chains representing over 3,000 stores nationwide (excluding Nunavut) in 85% of Health Regions. Data provided include the number of new antiviral prescriptions (for Tamiflu[oseltamivir] and Relenza [zanamivir]) and the total number of new prescriptions dispensed by Province/Territory and age group.
            * The average weekly proportion includes data from April 2011 to March 2015.
            Figure 5 - Text Description Influenza Outbreak Surveillance

            In week 17, eight new laboratory confirmed influenza outbreaks were reported: seven in long-term care facilities (LTCF) and one in an institution or community setting. Of the seven outbreaks with known strains or subtypes, all were due to influenza B.
            To date this season, 409 outbreaks have been reported. At week 17 in the 2014-15 season, 1,696 outbreaks were reported and in the 2013-14 season, 226 outbreaks were reported.
            Figure 6. Overall number of new laboratory-confirmed influenza outbreaksFigure 5 - Footnote1 by report week, Canada, 2015-2016

            Figure 6 - Footnote 1 All provinces and territories except NU report influenza outbreaks in long-term care facilities. All provinces and territories with the exception of NU and QC report outbreaks in hospitals. Outbreaks of influenza or influenza-like-illness in other facilities are reported to FluWatch but reporting varies between jurisdictions. Outbreak definitions are included at the end of the report.
            Return to Figure 5 - Footnote1referrer
            Figure 6 - Text Description Sentinel Pediatric Hospital Influenza Surveillance

            Paediatric Influenza Hospitalizations and Deaths

            In week 17, the number of laboratory-confirmed influenza-associated pediatric hospitlaizations slightly decreased. A total of 34 laboratory-confirmed influenza-associated pediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network (Figure 7). The largest proportion of hospitalizations were in children aged 2-4 years, accounting for 35% of the hospitalizations. Similar to the trend of increased laboratory detections of influenza B, 82% of pediatric hospitalizations reported in week 17 were due to influenza B.
            To date this season, 1,272 hospitalizations have been reported by the IMPACT network: 887 hospitalized cases (69%) were due to influenza A and 385 cases (31%) were due to influenza B. This season?s count of pediatric hospitalizations is nearly double that reported up to week 17 (676) in the 2014-15 season. The current year total number of cases also exceeds the total number of cases reported in the past five seasons.
            A total of 195 intensive care unit (ICU) admissions have been reported. Children aged 2 to 4 and 5 to 9 years accounted for 29% and 26% respectively of ICU admissions. A total of 131 ICU cases (67%) reported at least one underlying condition or comorbidity. Eight influenza-associated deaths have been reported which is above the number of deaths reported at this time in the last five season.
            Table 2 - Footnote x Suppressed to prevent residual disclosure.
            Return to Table 2 - Footnotexreferrer
            120 32 5 83 33 153 (12%)
            275 75 8 192 76 351 (28%)
            254 81 <5 Table 2 - Footnotex 104 358 (28%)
            180 45 <5 Table 2 - Footnotex 124 304 (24%)
            58 18 <5 Table 2 - Footnotex 48 106 (8%)
            887 251 22 614 385 1272 (100%)
            Figure 7. Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2015-16, paediatric and adult hospitalizations (≤16 years of age, IMPACT; ≥16 years of age, CIRN-SOS)

            Not included in Table 2 and Figure 7 are two IMPACT cases that were due to co-infections of influenza A and B.
            Figure 7 - Text Description Adult Influenza Hospitalizations and Deaths

            Overall, adult hospitalizations decreased in week 17. A total of 12 laboratory-confirmed influenza-associated adult (≥16 years of age) hospitalizations were reported by the Canadian Immunization Research Network Serious Outcome Surveillance (CIRN-SOS) (Figure 7). The majority of hospitalizations were in adults ≥65 years of age (67%) and due to influenza B (70%). In recent weeks, the weekly number of hospitalizations reported by CIRN has been decreasing and an increasing proportion of hospitalizations have been due to influenza B.
            To date this season, 1,131 hospitalizations have been reported by CIRN-SOS (Table 3). The majority of hospitalized cases were due to influenza A (82%) and the largest reported proportion was among adults ≥65 years of age (50%). One hundred and eighty-five intensive care unit (ICU) admissions have been reported of which 130 cases reported at least one underlying condition or comorbidity. A total of 50 deaths have been reported this season with the majority of deaths reported in adults ≥65 years of age (66%).
            Table 3 - Footnote x Suppressed to prevent residual disclosure.
            Return to Table 3 - Footnotexreferrer
            Table 3 - Footnotex <5 0 <5 <5 7 (1%)
            141 50 <5 Table 3 - Footnotex 41 182 (16%)
            330 104 <5 Table 3 - Footnotex 43 373(33%)
            445 124 24 297 120 565 (50%)
            <5 0 0 <5 <5 <5 (x%)
            23 283 28 612 208 1131
            82% 31% 3% 66% 18% 100%
            Figure 8. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group (≥16 year of age), Canada 2015-16

            Note: The number of hospitalizations reported through CIRN-SOS and IMPACT represents a subset of all influenza-associated adult and paediatric hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
            x - Suppressed to prevent residual disclosure.
            Figure 8 - Text Description Provincial/Territorial Influenza Hospitalizations and Deaths

            In week 17, the number of hospitalizations reported by participating provinces and territories decreased from the previous week (from 129 in week 16 to 93 in week 17)Footnote*. Influenza B accounted for the greatest proportion of hospitalizations (63%) in week 17. The largest proportion of cases reported was in adults ≥65 years of age (43%). Among hospitalizations with influenza B, children represented 31% of cases.
            Since the start of the 2015-16 season, 4,963 laboratory-confirmed influenza-associated hospitalizations have been reported. A total of 3,978 hospitalizations (80%) were due to influenza A and 985 (20%) were due to influenza B. Of the 522 ICU admissions reported, 269 (52%) were due to influenza A(H1N1). A total of 236 deaths have been reported; all but 33 were associated with influenza A (86%).
            Overall this season, hospitalizations have been reported more frequently among adults ≥65 years of age. The largest proportion of ICU admissions was reported in adults 45-64 years of age and the highest proportion of fatal cases was reported in adults ≥65 years of age. Pediatric (0-19 years) and young to middle-aged adults (20-44 years) accounted for 42% of all hospitalizations and 13% of all deaths reported to date this season. Similar to findings from the IMPACT network, there have been more pediatric hospitalizations reported to date compared to the year-end totals in each of the previous four influenza seasons. Figure 9. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada 2015-16

            Figure 9 - Text Description Footnote * Note: Influenza-associated hospitalizations are not reported to PHAC by the following Provinces and Territory: BC, NU, and QC. Only hospitalizations that require intensive medical care are reported by SK. ICU admissions are not distinguished among hospital admissions reported from ON. Data may also include cases reported by the IMPACT networks. The number of new influenza-associated hospitalizations and deaths reported for the current week may include cases from ON that occurred in previous weeks, as a result of retrospective updates to the cumulative total. It is important to note that the hospitalization or death does not have to be attributable to influenza, a positive laboratory test is sufficient for reporting.
            Return to footnote*referrer
            Footnote * Includes three hospitalizations for which age is unknown.
            Return to footnote1referrer
            See additional data on Reported Influenza Hospitalizations and Deaths in Canada: 2011-12 to 2015-16 on the Public Health Agency of Canada website.
            Influenza Strain Characterizations

            During the 2015-16 influenza season, the National Microbiology Laboratory (NML) has characterized 2,233 influenza viruses [209 A(H3N2), 1,230 A(H1N1) and 794 influenza B].
            Influenza A (H3N2): When tested by hemagglutination inhibition (HI) assays, 58 A(H3N2) viruses were antigenically characterized as A/Switzerland/9715293/2013-like using antiserum raised against cell-propagated A/Switzerland/9715293/2013.
            Sequence analysis was done on 151 A(H3N2) viruses. All viruses belonged to a genetic group for which most viruses were antigenically related to A/Switzerland/9715293/2013. A/Switzerland/9715293/2013 is the A(H3N2) component of the 2015-16 Northern Hemisphere's vaccine.
            Influenza A (H1N1): All of the 1,230 A(H1N1) viruses characterized were antigenically similar to A/California/7/2009, the A(H1N1) component of the 2015-16 influenza vaccine.
            Influenza B:A total of 162 influenza B viruses characterized were antigenically similar to the vaccine strain B/Phuket/3073/2013. A total of 632 influenza B viruses were characterized as B/Brisbane/60/2008-like, one of the influenza B components of the 2015-16 Northern Hemisphere quadrivalent influenza vaccine.
            The recommended components for the 2015-2016 Northern Hemisphere trivalent influenza vaccine included: an A/California/7/2009(H1N1)pdm09-like virus, an A/Switzerland/9715293/2013(H3N2)-like virus, and a B/Phuket/3073/2013 -like virus (Yamagata lineage). For quadrivalent vaccines, the addition of a B/Brisbane/60/2008-like virus (Victoria lineage) is recommended.
            The NML receives a proportion of the influenza positive specimens from provincial laboratories for strain characterization and antiviral resistance testing. Characterization data reflect the results of haemagglutination inhibition testing compared to the reference influenza strains recommended by WHO.
            .../


            "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerable citizens in our society, a life free of violence and fear."
            -Nelson Mandela

            Comment


            • #21
              FluWatch report: May 1 to May 21, 2016 (weeks 18-20)

              Overall Summary

              • In weeks 18-20, all influenza indicators declined from the previous weeks.
              • Elevated influenza B activity persisted in many regions across Canada: influenza B accounted for the majority of influenza detections in weeks 18-20. Additionally, the majority of outbreaks reported this week were due to Influenza B.
              • This increase in influenza B is expected as influenza B often shows up later in the flu season.
              • Hospitalizations, ICU admissions and deaths among the pediatric population, while declining, continue to remain above expected levels based on the past several influenza seasons.
              • For more information on the flu, see our Flu(influenza) web page.

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              Organization: Public Health Agency of Canada
              Date published: 2016-05-27

              Related Topics



              Are you a primary health care practitioner (General Practitioner, Nurse Practitioner or Registered Nurse) interested in becoming a FluWatch sentinel for the 2015-16 influenza season? Contact us at FluWatch@phac-aspc.gc.ca


              On this page

              Influenza/Influenza-like Illness Activity (geographic spread)

              Influenza activity continues to be reported in Canada; however, the number of regions reporting influenza activity decreased in weeks 18-20. During week 20, localized activity was reported in a total of six regions across Ontario and Nunavut. Sporadic activity levels were reported in 26 regions across all provinces and territories. A total of 13 regions reported no influenza activity and a total of 8 regions did not report data in week 20.
              Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, week 20




              Note: Influenza/ILI activity levels, as represented on this map, are assigned and reported by Provincial and Territorial Ministries of Health, based on laboratory confirmations, sentinel ILI rates and reported outbreaks. Please refer to detailed definitions at the end of the report. Maps from previous weeks, including any retrospective updates, are available in the mapping feature found in the Weekly Influenza Reports.
              Figure 1 - Text Description Laboratory Confirmed Influenza Detections

              In weeks 18-20, the percentage of tests positive for influenza continued to decrease [from 17% in week 17.0 to 9.4% in week 20], driven by the decline in influenza A. Compared to the previous five seasons, the percent positive (9.4%) reported in week 20 was above the five year average for that week and exceeded the expected levels (confidence interval 5.0-9.2%). With the late start to the 2015-16 influenza season, these elevated levels are not unexpected.
              Figure 2. Number of positive influenza tests and percentage of tests positive, by type, subtype and report week, Canada, 2015-16

              Figure 2 - Text Description Nationally in weeks 18-20, there were 1,555 positive influenza tests reported. Influenza B continues to account for an increasing proportion of influenza detections accounting for 80% of detections in weeks 18-20. Laboratory detections of influenza in the provinces of Ontario and Quebec accounted for 78% of all detections for week 20. To date, 73% of influenza detections have been influenza A and among those subtyped, the vast majority have been influenza A(H1N1) [91% (11,003/12,103)].
              Figure 3. Cumulative numbers of positive influenza specimens by type/subtype and province, Canada, 2015-16

              Note: Specimens from NT, YT, and NU are sent to reference laboratories in other provinces. Cumulative data includes updates to previous weeks.
              Figure 3 - Text Description In weeks 18-20, the number of laboratory detections decreased across all age groups, most notably among individuals under the age of 5 years. In week 20, Influenza B detections accounted for 85% of all detections (table 1).
              To date this season, detailed information on age and type/subtype has been received for 33,165 cases. Children and teenagers (0-19) accounted for 47% of influenza B cases and approximately one third of all influenza cases. Children and teenagers (0-19), young adults (20-44) and middle-aged adults (45-64) accounted for approximately an equal proportion of influenza A(H1N1) cases (26-29%).
              Table 1 - Footnote 1 Table 1 includes specimens for which demographic information was reported. These represent a subset of all positive influenza cases reported.
              Return to Table 1 - Footnote1referrer
              Table 1 - Footnote 2 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections.
              Return to Table 1 - Footnote2referrer
              Table 1 - Footnote 3 Unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available.
              Return to Table 1 - Footnote3referrer
              Table 1 - Footnote x Suppressed to prevent residual disclosure.
              Return to Table 1 - Footnotexreferrer
              24 <5 Table 1 - Footnotex 20 252 4036 1225 75 2736 1701 6229 19%
              11 <5 Table 1 - Footnotex 10 261 2081 700 101 1280 2649 5058 15%
              26 <5 <5 21 154 4764 1713 163 2888 2168 7981 24%
              52 9 6 37 95 5382 1792 199 3391 1088 7476 23%
              57 7 15 35 178 4453 1225 440 2788 1563 6421 19%
              170 23 24 123 940 20716 6655 978 13083 9169 33165 100%
              15% 14% 14% 72% 85% 62% 32% 5% 63% 28%
              For data on other respiratory virus detections see the Respiratory Virus Detections in Canada Report on the Public Health Agency of Canada website.
              Influenza-like Illness Consultation Rate

              The national ILI consultation rate remained constant from previous weeks from 31.1 per 1,000 patient visits in week 17, to 31.1 per 1,000 patient visits in week 20. The highest ILI consultation rate was found in the 0-4 years age group (65.0 per 1,000) and the lowest was found in the 20-64 years age group (23.4 per 1,000) (Figure 4).
              Figure 4. Influenza-like-illness (ILI) consultation rates by age group and week, Canada, 2015-16

              Delays in the reporting of data may cause data to change retrospectively. In BC, AB, and SK, data are compiled by a provincial sentinel surveillance program for reporting to FluWatch. Not all sentinel physicians report every week.
              Figure 4 - Text Description Pharmacy Surveillance

              In the period of weeks 18-20, the proportion of prescriptions for antivirals decreased by 73% compared to week 17. The antiviral prescriptions per 100,000 total prescriptions in week 20 was 6.0; this rate is lower than the five year historical average for week 20. The proportion of prescriptions for antivirals remains highest among children. In week 20, the proportion reported among children was 11.3 per 100,000 total prescriptions.
              Figure 5. Proportion of prescription sales for influenza antivirals by age group and week, Canada, 2015-16

              Note: Pharmacy sales data are provided to the Public Health Agency of Canada by Rx Canada Inc. and sourced from major retail drug chains representing over 3,000 stores nationwide (excluding Nunavut) in 85% of Health Regions. Data provided include the number of new antiviral prescriptions (for Tamiflu[oseltamivir] and Relenza [zanamivir]) and the total number of new prescriptions dispensed by Province/Territory and age group.
              * The average weekly proportion includes data from April 2011 to March 2015.
              Figure 5 - Text Description Influenza Outbreak Surveillance

              In weeks 18-20, fourteen new laboratory confirmed influenza outbreaks were reported: twelve in long-term care facilities (LTCF), one in a hospital and and one in an institution or community setting. Of the outbreaks with known strains or subtypes, six outbreaks were due to influenza B, one was due to A(H3N2) and three were due to influenza A(unsubtyped).
              To date this season, 423 outbreaks have been reported. At week 20 in the 2014-15 season, 1,724 outbreaks were reported and in the 2013-14 season, 260 outbreaks were reported.
              Figure 6. Overall number of new laboratory-confirmed influenza outbreaksFigure 5 - Footnote1 by report week, Canada, 2015-2016

              Figure 6 - Footnote 1 All provinces and territories except NU report influenza outbreaks in long-term care facilities. All provinces and territories with the exception of NU and QC report outbreaks in hospitals. Outbreaks of influenza or influenza-like-illness in other facilities are reported to FluWatch but reporting varies between jurisdictions. Outbreak definitions are included at the end of the report.
              Return to Figure 5 - Footnote1referrer
              Figure 6 - Text Description Sentinel Pediatric Hospital Influenza Surveillance

              Paediatric Influenza Hospitalizations and Deaths

              In weeks 18-20, 66 laboratory-confirmed influenza-associated pediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network (Figure 7). An equal proportion of hospitalizations were reported in children 6-23 months, 2-4 years and 5-9 years, accounting for 26%, 23% and 26% of the hospitalizations respectively. Similar to the trend of increased laboratory detections of influenza B, 88% of pediatric hospitalizations reported in weeks 18-20 were due to influenza B.
              To date this season, 1,337 hospitalizations have been reported by the IMPACT network: 893 hospitalized cases (67%) were due to influenza A and 444 cases (33%) were due to influenza B. This season?s count of pediatric hospitalizations is nearly double that reported up to week 20 in the 2014-15 season (n=697). The current year total number of cases also exceeds the total number of cases reported in the past five seasons.
              A total of 205 intensive care unit (ICU) admissions have been reported. Children aged 2 to 4 and 5 to 9 years accounted for 29% and 26% of ICU admissions respectively . A total of 131 ICU cases (64%) reported at least one underlying condition or comorbidity. Eight influenza-associated deaths have been reported.
              Table 2 - Footnote x Suppressed to prevent residual disclosure.
              Return to Table 2 - Footnotexreferrer
              122 32 <5 Table 2 - Footnotex 40 162 (12%)
              275 76 7 192 92 367 (27%)
              257 82 <5 Table 2 - Footnotex 114 371 (28%)
              181 46 <5 Table 2 - Footnotex 142 323 (24%)
              58 18 <5 Table 2 - Footnotex 56 114 (9%)
              893 254 21 618 444 1337 (100%)
              Figure 7. Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2015-16, paediatric and adult hospitalizations (≤16 years of age, IMPACT; ≥16 years of age, CIRN-SOS)

              Not included in Table 2 and Figure 7 are two IMPACT cases that were due to co-infections of influenza A and B.
              Figure 7 - Text Description Adult Influenza Hospitalizations and Deaths

              Surveillance for the 2015-2016 influenza season ended on April 30th, 2016.
              To date this season, 1,153 hospitalizations have been reported by CIRN-SOS (Table 3). The majority of hospitalized cases were due to influenza A (81%) and the largest reported proportion was among adults ≥65 years of age (50%). One hundred and ninety-one intensive care unit (ICU) admissions have been reported of which 132 cases reported at least one underlying condition or comorbidity. A total of 55 deaths have been reported this season with the majority of deaths reported in adults ≥65 years of age (62%).
              Table 3 - Footnote x Suppressed to prevent residual disclosure.
              Return to Table 3 - Footnotexreferrer
              Table 3 - Footnotex <5 0 <5 <5 Table 3 - Footnotex
              144 50 <5 Table 3 - Footnotex 46 190(16%)
              331 105 <5 Table 3 - Footnotex 46 377(33%)
              452 125 24 303 123 575 (50%)
              <5 Table 3 - Footnotex 0 <5 <5 <5 (x%)
              934 285 28 621 219 1153
              81% 31% 3% 66% 19% 100%
              Figure 8. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group (≥16 year of age), Canada 2015-16

              Note: The number of hospitalizations reported through CIRN-SOS and IMPACT represents a subset of all influenza-associated adult and paediatric hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
              x - Suppressed to prevent residual disclosure.
              Figure 8 - Text Description Provincial/Territorial Influenza Hospitalizations and Deaths

              Provincial/Territorial Influenza Hospitalizations and Deaths



              In week 20, 37 hospitalizations were reported by participating provinces and territoriesootnote*. Influenza B accounted for the greatest proportion of hospitalizations, accounting for 65% of hospitalizations reported in week 20. The largest proportion of cases reported was in adults 65+ years of age (49%). Among hospitalizations for influenza B, children (0-19 years) represented 41% of cases.
              Since the start of the 2015-16 season, 5,169 laboratory-confirmed influenza-associated hospitalizations have been reported. A total of 4,054 hospitalizations (78%) were due to influenza A and 1115 (22%) were due to influenza B. Of the 529 ICU admissions reported, 271 (51%) were due to influenza A(H1N1). A total of 255 deaths have been reported; all but 36 were associated with influenza A.
              Overall this season, hospitalizations have been reported more frequently among adults ≥65 years of age. The largest proportion of ICU admissions was reported in adults 45-64years of age and the highest proportion of fatal cases was reported in adults ≥65 years of age (figure 9). Pediatric (0-19 years) and young to middle-aged adults (20-44 years) accounted for 29% of all hospitalizations and 5% of all deaths reported to date this season. Similar to findings from the IMPACT network, there have been more pediatric hospitalizations reported to date compared to the year-end totals in each of the previous four influenza seasons.
              Figure 9. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada 2015-16

              Figure 9 - Text Description Footnote * Note: Influenza-associated hospitalizations are not reported to PHAC by the following Provinces and Territory: BC, NU, and QC. Only hospitalizations that require intensive medical care are reported by SK. ICU admissions are not distinguished among hospital admissions reported from ON. Data may also include cases reported by the IMPACT networks. The number of new influenza-associated hospitalizations and deaths reported for the current week may include cases from ON that occurred in previous weeks, as a result of retrospective updates to the cumulative total. It is important to note that the hospitalization or death does not have to be attributable to influenza, a positive laboratory test is sufficient for reporting.
              Return to footnote*referrer
              Footnote * Includes three hospitalizations for which age is unknown.
              Return to footnote1referrer
              See additional data on Reported Influenza Hospitalizations and Deaths in Canada: 2011-12 to 2015-16 on the Public Health Agency of Canada website.
              Influenza Strain Characterizations

              During the 2015-16 influenza season, the National Microbiology Laboratory (NML) has characterized 2,678 influenza viruses [217 A(H3N2), 1,367 A(H1N1) and 1094 influenza B].
              Influenza A (H3N2):When tested by hemagglutination inhibition (HI) assays, 64 A(H3N2) viruses were antigenically characterized as A/Switzerland/9715293/2013-like using antiserum raised against cell-propagated A/Switzerland/9715293/2013.
              Sequence analysis was done on 153 A(H3N2) viruses. All viruses belonged to a genetic group for which most viruses were antigenically related to A/Switzerland/9715293/2013. A/Switzerland/9715293/2013 is the A(H3N2) component of the 2015-16 Northern Hemisphere's vaccine.
              Influenza A (H1N1): All of the 1,367 A(H1N1) viruses characterized were antigenically similar to A/California/7/2009, the A(H1N1) component of the 2015-16 influenza vaccine.
              Influenza B: A total of 232 influenza B viruses characterized were antigenically similar to the vaccine strain B/Phuket/3073/2013. A total of 862 influenza B viruses were characterized as B/Brisbane/60/2008-like, one of the influenza B components of the 2015-16 Northern Hemisphere quadrivalent influenza vaccine.
              The recommended components for the 2015-2016 Northern Hemisphere trivalent influenza vaccine included: an A/California/7/2009(H1N1)pdm09-like virus, an A/Switzerland/9715293/2013(H3N2)-like virus, and a B/Phuket/3073/2013 -like virus (Yamagata lineage). For quadrivalent vaccines, the addition of a B/Brisbane/60/2008-like virus (Victoria lineage) is recommended.
              The NML receives a proportion of the influenza positive specimens from provincial laboratories for strain characterization and antiviral resistance testing. Characterization data reflect the results of haemagglutination inhibition testing compared to the reference influenza strains recommended by WHO.

              .../

              "Safety and security don't just happen, they are the result of collective consensus and public investment. We owe our children, the most vulnerable citizens in our society, a life free of violence and fear."
              -Nelson Mandela

              Comment


              • #22
                FluWatch report: May 22 to June 18, 2016 (weeks 21-24)

                Overall Summary

                • Overall, influenza activity continues to decrease across Canada and has reached interseasonal levels.
                • Sporadic activity is being reported in several parts of Canada; however, the majority of regions are reporting no influenza activity.
                • No influenza outbreaks have been reported since week 22 (beginning of June).
                • Influenza-associated hospitalizations continue to decrease. Ten hospitalizations were reported in week 24
                • For more information on the flu, see our Flu (influenza) web page.
                Many thanks to all the sentinels participating in our influenza-like illness surveillance network. Your hard work is greatly appreciated!

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                Organization: Public Health Agency of Canada
                Date published: 2016-06-24

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                Are you a primary health care practitioner (General Practitioner, Nurse Practitioner or Registered Nurse) interested in becoming a FluWatch sentinel for the 2015-16 influenza season? Contact us at FluWatch@phac-aspc.gc.ca


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                Influenza/Influenza-like Illness Activity (geographic spread)

                In week 24, influenza activity continues to be reported in parts of Canada. Sporadic activity was reported in 14 regions across six provinces (BC, AB, MB, ON, QC, NB and NU). A total of 34 regions reported no influenza activity.
                Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, week 24




                Note: Influenza/ILI activity levels, as represented on this map, are assigned and reported by Provincial and Territorial Ministries of Health, based on laboratory confirmations, sentinel ILI rates and reported outbreaks. Please refer to detailed definitions at the end of the report. Maps from previous weeks, including any retrospective updates, are available in the mapping feature found in the Weekly Influenza Reports.
                Figure 1 - Text Description Laboratory Confirmed Influenza Detections

                In weeks 21-24, the percentage of tests positive for influenza continued to decrease [from 6.2% in week 21 to 1.1% in week 24]. Compared to the previous five seasons, the percent positive (1.1%) reported in week 24 was within expected levels (confidence interval 1.0-2.6%) and has retuned to interseasonal levels.
                Figure 2. Number of positive influenza tests and percentage of tests positive, by type, subtype and report week, Canada, 2015-16

                Figure 2 - Text Description Nationally in weeks 21-24, there were 389 positive influenza tests reported. Influenza B continues to account for the majority of influenza detections, representing 79% of detections in weeks 21-24. Overall in week 24, laboratory detections of influenza were low across Canada with total of 24 influenza detections reported. To date, 72% of influenza detections have been influenza A and among those subtyped, the vast majority have been influenza A(H1N1) [91% (11019/12147)].
                Figure 3. Cumulative numbers of positive influenza specimens by type/subtype and province, Canada, 2015-16

                Note: Specimens from NT, YT, and NU are sent to reference laboratories in other provinces. Cumulative data includes updates to previous weeks.
                Figure 3 - Text Description To date this season, detailed information on age and type/subtype has been received for 33,414 cases. Children and teenagers (0-19yrs) accounted for 48% of influenza B cases and approximately one third of all influenza cases. Children and teenagers (0-19yrs), young adults (20-44yrs) and middle-aged adults (45-64yrs) accounted for approximately an equal proportion of influenza A(H1N1) cases.
                Table 1 - Footnote 1 Table 1 includes specimens for which demographic information was reported. These represent a subset of all positive influenza cases reported.
                Return to Table 1 - Footnote1referrer
                Table 1 - Footnote 2 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections.
                Return to Table 1 - Footnote2referrer
                Table 1 - Footnote 3 Unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available.
                Return to Table 1 - Footnote3referrer
                Table 1 - Footnote x Suppressed to prevent residual disclosure.
                Return to Table 1 - Footnotexreferrer
                9 <5 <5 7 60 4533 1714 76 2743 1768 6305 19%
                9 <5 <5 <5 25 2408 1026 101 1281 2695 5105 15%
                14 <5 <5 8 14 5816 2758 166 2892 2197 8017 24%
                <5 0 0 <5 46 6396 2797 201 3398 1103 7505 22%
                15 <5 6 Table 1 - Footnotex 42 4863 1624 446 2793 1610 6482 19%
                48 11 12 25 187 24016 9919 990 13107 9373 33414 100%
                20% 23% 25% 52% 80% 72% 41% 4% 55% 28%
                For data on other respiratory virus detections see the Respiratory Virus Detections in Canada Report on the Public Health Agency of Canada website.
                Influenza-like Illness Consultation Rate

                The national ILI consultation rate decreased from previous weeks from 30.1 per 1,000 patient visits in week 22, to 13.4 per 1,000 patient visits in week 24. The ILI rate for week 21 was lower than expected due to a low response rate resulting from a technical error in data collection. In week 24, the highest ILI consultation rate was found in the 5-19 years age group (30.3 per 1,000) and the lowest was found in the 0-4 years age group (3.6 per 1,000) (Figure 4).
                Figure 4. Influenza-like-illness (ILI) consultation rates by age group and week, Canada, 2015-16

                Delays in the reporting of data may cause data to change retrospectively. In BC, AB, and SK, data are compiled by a provincial sentinel surveillance program for reporting to FluWatch. Not all sentinel physicians report every week.
                Figure 4 - Text Description Pharmacy Surveillance

                In the period of weeks 21-24, the proportion of prescriptions for antivirals continued to decrease steadily to 2.9 antiviral prescriptions per 100,000 total prescriptions in week 24. This rate is lower than the five year historical average for week 24. The proportion of prescriptions for antivirals remains highest among children. In week 24, the proportion reported among children was 8.1 per 100,000 total prescriptions.
                Figure 5. Proportion of prescription sales for influenza antivirals by age group and week, Canada, 2015-16

                Note: Pharmacy sales data are provided to the Public Health Agency of Canada by Rx Canada Inc. and sourced from major retail drug chains representing over 3,000 stores nationwide (excluding Nunavut) in 85% of Health Regions. Data provided include the number of new antiviral prescriptions (for Tamiflu[oseltamivir] and Relenza [zanamivir]) and the total number of new prescriptions dispensed by Province/Territory and age group.
                * The average weekly proportion includes data from April 2011 to March 2015.
                Figure 5 - Text Description Influenza Outbreak Surveillance

                In weeks 21-24, four new laboratory confirmed influenza outbreaks were reported: two in long-term care facilities (LTCF) and two in hospitals. All outbreaks were reported in weeks 21 and 22. Three outbreaks were due to influenza B and one was due to influenza A(unsubtyped).
                To date this season, 427 outbreaks have been reported. At week 24 in the 2014-15 season, 1,732 outbreaks were reported and in the 2013-14 season, 268 outbreaks were reported.
                Figure 6. Overall number of new laboratory-confirmed influenza outbreaksFigure 5 - Footnote1 by report week, Canada, 2015-2016

                Figure 6 - Footnote 1 All provinces and territories except NU report influenza outbreaks in long-term care facilities. All provinces and territories with the exception of NU and QC report outbreaks in hospitals. Outbreaks of influenza or influenza-like-illness in other facilities are reported to FluWatch but reporting varies between jurisdictions. Outbreak definitions are included at the end of the report.
                Return to Figure 5 - Footnote1referrer
                Figure 6 - Text Description Sentinel Pediatric Hospital Influenza Surveillance

                Paediatric Influenza Hospitalizations and Deaths

                In weeks 21-24, 16 laboratory-confirmed influenza-associated pediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network (Figure 7). The majority of hospitalizations (81%) were due to influenza B.
                A total of 222 intensive care unit (ICU) admissions have been reported. Children aged 2 to 4 and 5 to 9 years accounted for 27% and 26% of ICU admissions respectively. A total of 158 ICU cases (71%) reported at least one underlying condition or comorbidity. Eight influenza-associated deaths have been reported.
                To date this season, 1,364 hospitalizations have been reported by the IMPACT network: 900 cases (66%) were due to influenza A and 464 cases (34%) were due to influenza B. This season's count of pediatric hospitalizations is nearly double that reported up to week 24 in the 2014-15 season (N=711). The current year total number of cases also exceeds the total number of cases reported in the past five seasons.
                Table 2 - Footnote x Suppressed to prevent residual disclosure.
                Return to Table 2 - Footnotexreferrer
                122 33 <5 Table 2 - Footnotex 40 162 (12%)
                281 80 7 194 99 380 (28%)
                255 80 5 170 119 374 (27%)
                183 49 <5 Table 2 - Footnotex 146 329 (24%)
                59 18 <5 Table 2 - Footnotex 60 119 (9%)
                900 260 21 619 464 1364 (100%)
                Figure 7. Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2015-16, paediatric and adult hospitalizations (≤16 years of age, IMPACT; ≥16 years of age, CIRN-SOS)

                Not included in Table 2 and Figure 7 are two IMPACT cases that were due to co-infections of influenza A and B.
                Figure 7 - Text Description Adult Influenza Hospitalizations and Deaths

                Surveillance for the 2015-2016 influenza season ended on April 30th, 2016.
                For the 2015-16 season, 1,153 hospitalizations have been reported by CIRN-SOS (Table 3). The majority of hospitalized cases were due to influenza A (81%) and the largest reported proportion was among adults ≥65 years of age (50%). One hundred and ninety-one intensive care unit (ICU) admissions have been reported of which 132 cases reported at least one underlying condition or comorbidity. A total of 55 deaths have been reported this season with the majority of deaths reported in adults ≥65 years of age (62%).
                Table 3 - Footnote x Suppressed to prevent residual disclosure.
                Return to Table 3 - Footnotexreferrer
                Table 3 - Footnotex <5 0 <5 <5 Table 3 - Footnotex
                144 50 <5 Table 3 - Footnotex 46 190(16%)
                331 105 <5 Table 3 - Footnotex 46 377(33%)
                452 125 24 303 123 575 (50%)
                <5 Table 3 - Footnotex 0 <5 <5 <5 (x%)
                934 285 28 621 219 1153
                81% 31% 3% 66% 19% 100%
                Figure 8. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group (≥16 year of age), Canada 2015-16

                Note: The number of hospitalizations reported through CIRN-SOS and IMPACT represents a subset of all influenza-associated adult and paediatric hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
                x - Suppressed to prevent residual disclosure.
                Figure 8 - Text Description Provincial/Territorial Influenza Hospitalizations and Deaths

                In week 24, 10 hospitalizations were reported by participating provinces and territoriesFootnote*. In total, 98 hospitalizations were reported in weeks 21-24, with the number of cases decreasing each week. Three ICU admissions were reported during the week 21-24 period.
                Since the start of the 2015-16 season, 5,267 laboratory-confirmed influenza-associated hospitalizations have been reported. A total of 4,094 hospitalizations (78%) were due to influenza A and 1,173 (22%) were due to influenza B. Of the 537 ICU admissions reported, 474 (88%) were due to influenza A. A total of 264 deaths have been reported; all but 41 were associated with influenza A.
                Overall this season, hospitalizations have been reported more frequently among adults ≥65 years of age. The largest proportion of ICU admissions was reported in adults 45-64years of age and the highest proportion of fatal cases was reported in adults ≥65 years of age (Figure 9). Pediatric (0-19 years) accounted for 29% of all hospitalizations and 5% of all deaths reported to date this season. Similar to findings from the IMPACT network, there have been more pediatric hospitalizations reported to date compared to the year-end totals in each of the previous four influenza seasons.
                Figure 9. Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada 2015-16

                Figure 9 - Text Description Footnote * Note: Influenza-associated hospitalizations are not reported to PHAC by the following Provinces and Territory: BC, NU, and QC. Only hospitalizations that require intensive medical care are reported by SK. ICU admissions are not distinguished among hospital admissions reported from ON. Data may also include cases reported by the IMPACT networks. The number of new influenza-associated hospitalizations and deaths reported for the current week may include cases from ON that occurred in previous weeks, as a result of retrospective updates to the cumulative total. It is important to note that the hospitalization or death does not have to be attributable to influenza, a positive laboratory test is sufficient for reporting.
                Return to footnote*referrer
                Footnote * Includes three hospitalizations for which age is unknown.
                Return to footnote1referrer
                See additional data on Reported Influenza Hospitalizations and Deaths in Canada: 2011-12 to 2015-16 on the Public Health Agency of Canada website.
                Influenza Strain Characterizations

                During the 2015-16 influenza season, the National Microbiology Laboratory (NML) has characterized 2,871 influenza viruses [236 A(H3N2), 1,450 A(H1N1) and 1,185 influenza B].
                Influenza A (H3N2): When tested by hemagglutination inhibition (HI) assays, 75 A(H3N2) viruses were antigenically characterized as A/Switzerland/9715293/2013-like using antiserum raised against cell-propagated A/Switzerland/9715293/2013.
                Sequence analysis was done on 161 A(H3N2) viruses. All viruses belonged to a genetic group for which most viruses were antigenically related to A/Switzerland/9715293/2013. A/Switzerland/9715293/2013 is the A(H3N2) component of the 2015-16 Northern Hemisphere's vaccine.
                Influenza A (H1N1): All of the 1,450 A(H1N1) viruses characterized were antigenically similar to A/California/7/2009, the A(H1N1) component of the 2015-16 influenza vaccine.
                Influenza B: A total of 248 influenza B viruses characterized were antigenically similar to the vaccine strain B/Phuket/3073/2013. A total of 937 influenza B viruses were characterized as B/Brisbane/60/2008-like, one of the influenza B components of the 2015-16 Northern Hemisphere quadrivalent influenza vaccine.
                The NML receives a proportion of the influenza positive specimens from provincial laboratories for strain characterization and antiviral resistance testing. Characterization data reflect the results of haemagglutination inhibition testing compared to the reference influenza strains recommended by WHO.
                ...


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