FluWatch report: January 4 to January 10, 2015 (Week 1)
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FluWatch report: January 4 to January 10, 2015 (Week 1) (PDF Version - 385 KB- 10 pages)
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Overall Summary
Are you a primary health care practitioner (General Practitioner, Nurse Practitioner or Registered Nurse) interested in becoming a FluWatch sentinel for the 2014-15 influenza season? Contact us at FluWatch@phac-aspc.gc.ca
Influenza/ILI Activity (geographic spread)
In week 01, 22 regions reported widespread activity: in BC(3), AB(5), SK, MB(2), ON(5), QC(3), NF(3). The same five regions in Alberta have reported widespread activity for the past 3 weeks. Thirteen regions reported localized activity: in SK, MB(3), ON, QC(3), NB(4) and PE and eight regions reported sporadic activity: in BC(2), SK, ON, NB(2), NF and NWT.
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 on the FluWatch website.
Text equivalent for figure 1Map of overall Influenza activity level by province and territory, Canada
Influenza and Other Respiratory Virus Detections
The number of positive tests decreased from 5,313 in week 53 to 4,579 in week 01. The percentage of positive influenza tests also decreased from 34.4% to 28.5% (Figure 2). This may be an indication that we have reached the peak in laboratory detections with the percent positive for influenza peaking in week 52 (35%) and the number of positive influenza tests peaking in week 53 (5,313). To date, 98% of influenza detections have been influenza A, and 99.8% of those subtyped have been A(H3) (Table 1). The timing of the season and predominant A(H3N2) subtype is similar to the pattern observed during the 2012-13 influenza season when percent positive for influenza peaked in week 52 (35%). To date, among the cases of influenza with reported age, the largest proportion was in adults ≥65 years of age (63%) (Table 2).
In week 01, the number of positive RSV tests increased to 1,001 RSV detections up from 979 RSV detections in week 53. RSV remains the second most frequently detected virus after influenza. Detections of RSV since week 38 have been higher than in the previous season while detections of parainfluenza and adenovirus continue to follow their seasonal patterns of broad winter circulation (Figure 3).
For more details, see the weekly Respiratory Virus Detections in Canada Report.
RSV: Respiratory syncytial virus; hMPV: Human metapneumovirus
Text equivalent for figure 3Overall Number of Influenza Outbreaks, Canada, by Report Week, 2013-2014
Antiviral Resistance
During the 2014-2015 influenza season, NML has tested 235 influenza viruses for resistance to oseltamivir and 233influenza viruses for resistance to zanamivir and all were sensitive to both agents. A total of 339 (99.7%) of influenza A viruses tested for amantadine resistance were resistant (Table 3).
Influenza Strain Characterizations
During the 2014-2015 influenza season, the National Microbiology Laboratory (NML) has characterized 89 influenza viruses [55 A(H3N2), 2 A(H1N1) and 32 influenza B]. The majority of circulating influenza B and A(H1N1) viruses have been antigenically similar (good match) to the recommended strains for the 2014-15 seasonal influenza vaccine, while the majority of A(H3N2) viruses have shown evidence of an antigenic drift (sub-optimal match) from the vaccine strain.
Influenza A (H3N2): When tested by hemagglutination inhibition (HI) assay (n=55), one virus was antigenically similar to A/Texas/50/2012, five showed reduced titers to A/Texas/50/2012 and 49 were antigenically similar to A/Switzerland/9715293/2013, which is the influenza A(H3N2) component recommended for the 2015 Southern Hemisphere influenza vaccine. Additionally, 250 A(H3N2) viruses were unable to be tested by HI assay; however, sequence analysis showed that 249 belonged to a genetic group that typically shows reduced titers to A/Texas/50/2012. Influenza A(H1N1): Two A(H1N1) viruses characterized were antigenically similar to A/California/7/2009. Influenza B: Of the 32 influenza B viruses characterized, 29 viruses were antigenically similar to B/Massachusetts/2/2012, and three viruses showed reduced titers (Figure 4).
The NML receives a proportion of the number of influenza positive specimens from provincial laboratories for strain characterization and antiviral resistance testing. Characterization data reflect the results of haemagglutination inhibition (HAI) testing compared to the reference influenza strains recommended by WHO.
The recommended components for the 2014-2015 northern hemisphere trivalent influenza vaccine include: an A/California/7/2009(H1N1)pdm09-like virus, an A/Texas/50/2012 (H3N2)-like virus, and a B/Massachusetts/2/2012-like virus (Yamagata lineage). For quadrivalent vaccines, the addition of a B/Brisbane/60/2008-like virus is recommended.
Text equivalent for figure 4Influenza strain characterizations, Canada, 2013-2014, N =3
Influenza-like Illness (ILI) Consultation Rate
The national influenza-like-illness (ILI) consultation decreased in week 01 to 50.1 consultations per 1,000, which is above expected levels for week 01 (Figure 5). The rates were highest among the 0 to 4 years of age group (269.8 consultations per 1,000) and lowest among the adults ≥65 years of age (12.0 consultations per 1,000).
Text equivalent for figure 5Influenza-like-illness (ILI) consultation rates by report week, compared to the 1996-97 through to 2012-13 seasons (with pandemic data suppressed), Canada, 2013-2014
Influenza Outbreak Surveillance
In week 01, 195 new outbreaks of influenza were reported: 152 in long-term care facilities (LTCF), 12 in hospitals and 31 in institutional or community settings (Figure 6). Among the outbreaks in which the influenza subtype was known, two LTCF outbreaks and four institutional or community setting outbreaks were associated with A(H3N2). To date this season, 623 outbreaks in LTCFs have been reported. The number of outbreaks reported since week 47 is above those of previous seasons and is similar to the numbers reported during the 2012-13 influenza season when influenza A(H3N2) also predominated. The majority of the outbreaks with known subtypes are attributable to A(H3N2).
Figure 6. Overall number of new influenza outbreaks by report week, Canada, 2014-2015
Text equivalent for figure 6Overall number of new influenza outbreaks by report week, Canada, 2013-2014
Pharmacy Surveillance
During week 01, the proportion of prescriptions for antivirals decreased to 918.5 antiviral prescriptions per 100,000 total prescriptions (down from 969.6 per 100,000 total prescriptions). The rate for antivirals since week 48 has been higher than the previous three seasons (Figure 7). The rate in age groups except children decreased in week 01. The antiviral prescription rate remains the highest amongst seniors at 1,552.8 per 100,000 total prescriptions.
Text equivalent for figure 7Proportion of prescription sales for influenza antivirals by age-group and week, Canada, 2013-14
Sentinel Hospital Influenza Surveillance
Paediatric Influenza Hospitalizations and Deaths (IMPACT)
In week 01, 44 laboratory-confirmed influenza-associated paediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network: 41 cases of influenza A and one case of influenza B(Figure 8a). Among the reported cases, 21 (48%) were <2 years of age, 19 (43%) were 2 to 9 years of age and 4 (9%) were 10-16 years of age. Four cases were admitted to the ICU. To date this season, 358 hospitalizations have been reported by the IMPACT network, 337 (94%) of which were cases of influenza A. Among cases for which the influenza A subtype was reported, 98% (127/129) were A(H3N2). Children <5 years of age represented 61% of cases (Table 4). To date, 38 cases were admitted to the ICU, of which 22 (58%) were 2 to 9 years of age (Figure 9a).
Note: The number of hospitalizations reported through IMPACT represents a subset of all influenza-associated paediatric hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
Adult Influenza Hospitalizations and Deaths (PCIRN)
In week 01, 106 laboratory-confirmed influenza-associated adult (≥16 years of age) hospitalizations were reported by the PHAC/CIHR Influenza Research Network (PCIRN) Serious Outcomes Surveillance (SOS) network, compared to 137 in week 53. Among cases in week 01, 96 cases (91%) were in adults over the age of 65 and 105 cases (99%) had influenza A (Figure 8b). To date this season, 672 cases have been reported; 664 (99%) with influenza A. The majority of cases (85%) were among adults ≥65 years of age (Table 5). Forty ICU admissions have been reported and the majority of cases (75%) were adults ≥65 years of age, most (69%) with known underlying conditions or comorbidities. Twenty-six deaths have been reported, all but three were adults >65 years of age (Figure 9b).
Note: The number of hospitalizations reported through PCIRN represents a subset of all influenza-associated adult hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
Figure 8 - Number of cases of influenza reported by sentinel hospital networks, by week, Canada, 2014-15
A) Paediatric hospitalizations (≤16 years of age, IMPACT)
B) Adult hospitalizations (≥16 year of age, PCIRN-SOS)
Text equivalent for figure 8bNumber of cases of influenza reported by sentinel hospital networks, by week, Canada, 2013-14: Adult hospitalizations (>16 year of age, PCIRN-SOS)
Figure 9 - Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada, 2014-15
A) Paediatric hospitalizations (≤16 years of age, IMPACT)
Text equivalent for figure 9aPercentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada, 2013-14: Paediatric hospitalizations (≤16 years of age, IMPACT)
B) Adult hospitalizations (≥16 year of age, PCIRN-SOS)
Text equivalent for figure 9bPercentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada, 2013-14: Adult hospitalizations (≥16 year of age, PCIRN-SOS)
Provincial/Territorial Influenza Hospitalizations and Deaths
In week 01, 566 laboratory-confirmed influenza-associated hospitalizations were reported from participating provinces and territories*; all but eight with influenza A, and 79% were patients ≥65 years of age. Since the start of the 2014-15 season, 2161 hospitalizations have been reported; 2121 (98%) with influenza A. Among cases for which the subtype of influenza A was reported, 99.6% (914/917) were A(H3N2). The majority of cases (69%) were ≥65 years of age (Table 6). Sixty two ICU admissions have been reported in adults ≥65 years of age with influenza A and 34 ICU admissions have been reported in adults 20-64 years. A total of 125 deaths have been reported since the start of the season: one child <5 years of age, one child 5-19 years, six adults 20-64 years, and 117 adults ≥65 years of age. Adults 65 years of age or older represent 94% of all deaths reported this season. Detailed clinical information (e.g. underlying medical conditions) is not known for these cases.
* Note: Influenza-associated hospitalizations are not reported to PHAC by the following Provinces and Territory: BC, NU, QC, and NB. Only hospitalizations that require intensive medical care are reported by Saskatchewan. ICU admissions are not distinguished among hospital admissions reported from Ontario. Data may also include cases reported by the IMPACT and PCIRN networks. The number of new influenza-associated hospitalizations and deaths reported for the current week may include cases from Ontario 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.
See additional data on Reported Influenza Hospitalizations and Deaths in Canada: 2009-10 to 2014-15 on the Public Health Agency of Canada website.
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http://www.phac-aspc.gc.ca/fluwatch/.../index-eng.php
Posted 2015-01-16 For readers interested in the PDF version, the document is available for downloading or viewing:
FluWatch report: January 4 to January 10, 2015 (Week 1) (PDF Version - 385 KB- 10 pages)
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Overall Summary
- In week 1, seven of the thirteen provinces and territories reported widespread activity within their jurisdictions- the highest levels reported to date.
- Similar to the previous week, there were a large number of newly-reported laboratory-confirmed outbreaks of influenza: 195 outbreaks in 9 provinces, of which 152 were in long-term care facilities (LTCF). This is record number of LTCF outbreaks reported over the last five influenza seasons.
- The percent positive for laboratory detections of influenza decreased in week 01 in Canada - suggesting that the seasonal influenza has peaked.
- Overall in week 01, many indicators such as laboratory detections, prescriptions for antiviral medications, paediatric hospitalizations and ILI consultations rate have decreased.
- To date, the NML has found that the majority of A(H3N2) influenza specimens are not optimally matched to the vaccine strain. This may result in reduced vaccine effectiveness against the A(H3N2) virus. However, the vaccine can still provide some protection against A(H3N2) influenza illness and can offer protection against other influenza strains such as A(H1N1) and B
Are you a primary health care practitioner (General Practitioner, Nurse Practitioner or Registered Nurse) interested in becoming a FluWatch sentinel for the 2014-15 influenza season? Contact us at FluWatch@phac-aspc.gc.ca
Influenza/ILI Activity (geographic spread)
In week 01, 22 regions reported widespread activity: in BC(3), AB(5), SK, MB(2), ON(5), QC(3), NF(3). The same five regions in Alberta have reported widespread activity for the past 3 weeks. Thirteen regions reported localized activity: in SK, MB(3), ON, QC(3), NB(4) and PE and eight regions reported sporadic activity: in BC(2), SK, ON, NB(2), NF and NWT.
Figure 1. Map of overall influenza/ILI activity level by province and territory, Canada, Week 1
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 on the FluWatch website.
Text equivalent for figure 1Map of overall Influenza activity level by province and territory, Canada
Influenza and Other Respiratory Virus Detections
The number of positive tests decreased from 5,313 in week 53 to 4,579 in week 01. The percentage of positive influenza tests also decreased from 34.4% to 28.5% (Figure 2). This may be an indication that we have reached the peak in laboratory detections with the percent positive for influenza peaking in week 52 (35%) and the number of positive influenza tests peaking in week 53 (5,313). To date, 98% of influenza detections have been influenza A, and 99.8% of those subtyped have been A(H3) (Table 1). The timing of the season and predominant A(H3N2) subtype is similar to the pattern observed during the 2012-13 influenza season when percent positive for influenza peaked in week 52 (35%). To date, among the cases of influenza with reported age, the largest proportion was in adults ≥65 years of age (63%) (Table 2).
Figure 2. Number of positive influenza tests and percentage of tests positive, by type, subtype and report week, Canada, 2014-15
Text equivalent for figure 2Number of positive influenza tests and percentage of tests positive, by type, subtype and report week, Canada, 2013-14
In week 01, the number of positive RSV tests increased to 1,001 RSV detections up from 979 RSV detections in week 53. RSV remains the second most frequently detected virus after influenza. Detections of RSV since week 38 have been higher than in the previous season while detections of parainfluenza and adenovirus continue to follow their seasonal patterns of broad winter circulation (Figure 3).
For more details, see the weekly Respiratory Virus Detections in Canada Report.
Figure 3. Number of positive laboratory tests for other respiratory viruses by report week, Canada, 2014-15
RSV: Respiratory syncytial virus; hMPV: Human metapneumovirus
Text equivalent for figure 3Overall Number of Influenza Outbreaks, Canada, by Report Week, 2013-2014
B Total | ||||||||||
1 Specimens from NT, YT, and NU are sent to reference laboratories in other provinces. Cumulative data includes updates to previous weeks. 2 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections. UnS: unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available. |
||||||||||
807 | 0 | 264 | 543 | 12 | 1699 | 2 | 726 | 971 | 39 | |
394 | 0 | 257 | 137 | 32 | 3517 | 2 | 3279 | 236 | 152 | |
104 | 0 | 0 | 104 | 0 | 898 | 0 | 0 | 898 | 5 | |
267 | 0 | 41 | 226 | 7 | 617 | 0 | 186 | 431 | 12 | |
1216 | 0 | 305 | 911 | 11 | 4622 | 5 | 1906 | 2711 | 59 | |
1332 | 0 | 0 | 1332 | 66 | 8301 | 3 | 422 | 7876 | 245 | |
37 | 0 | 0 | 37 | 0 | 70 | 0 | 5 | 65 | 2 | |
25 | 0 | 12 | 13 | 2 | 72 | 0 | 29 | 43 | 9 | |
8 | 0 | 8 | 0 | 0 | 23 | 1 | 20 | 2 | 1 | |
130 | 0 | 0 | 130 | 0 | 342 | 0 | 53 | 289 | 2 | |
4320 | 0 | 887 | 3433 | 130 | 20161 | 13 | 6626 | 13522 | 526 | |
97.1% | 0.0% | 20.5% | 79.5% | 2.9% | 97.5% | 0.1% | 32.9% | 67.1% | 2.5% |
Total | Total | |||||||||||
1 Specimens from NT, YT, and NU are sent to reference laboratories in other provinces. Cumulative data includes updates to previous weeks. 2 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections. 3 Table 2 includes specimens for which demographic information was reported. These represent a subset of all positive influenza cases reported. UnS: unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available. |
||||||||||||
126 | 0 | 17 | 109 | 10 | 1210 | 4 | 520 | 686 | 55 | 1265 | 6.8% | |
81 | 0 | 13 | 68 | 8 | 1085 | 0 | 622 | 463 | 62 | 1147 | 6.1% | |
256 | 0 | 35 | 221 | 15 | 2127 | 1 | 870 | 1256 | 77 | 2204 | 11.8% | |
325 | 0 | 36 | 289 | 28 | 2229 | 1 | 759 | 1469 | 99 | 2328 | 12.5% | |
1800 | 0 | 240 | 1560 | 43 | 11525 | 4 | 3561 | 7960 | 194 | 11719 | 62.7% | |
3 | 0 | 1 | 2 | 1 | 30 | 0 | 18 | 12 | 1 | 31 | 0.2% | |
2591 | 0 | 342 | 2249 | 105 | 18206 | 10 | 6350 | 11846 | 488 | 18694 | 100.0% | |
96.1% | 0.0% | 13.2% | 86.8% | 3.9% | 97.4% | 0.1% | 34.9% | 65.1% | 2.6% |
Antiviral Resistance
During the 2014-2015 influenza season, NML has tested 235 influenza viruses for resistance to oseltamivir and 233influenza viruses for resistance to zanamivir and all were sensitive to both agents. A total of 339 (99.7%) of influenza A viruses tested for amantadine resistance were resistant (Table 3).
* NA - not applicable | ||||||
206 | 0 | 204 | 0 | 338 | 337 (99.7%) | |
2 | 0 | 2 | 0 | 2 | 2 (100%) | |
27 | 0 | 27 | 0 | NA * | NA * | |
235 | 0 | 235 | 0 | 340 | 339 |
During the 2014-2015 influenza season, the National Microbiology Laboratory (NML) has characterized 89 influenza viruses [55 A(H3N2), 2 A(H1N1) and 32 influenza B]. The majority of circulating influenza B and A(H1N1) viruses have been antigenically similar (good match) to the recommended strains for the 2014-15 seasonal influenza vaccine, while the majority of A(H3N2) viruses have shown evidence of an antigenic drift (sub-optimal match) from the vaccine strain.
Influenza A (H3N2): When tested by hemagglutination inhibition (HI) assay (n=55), one virus was antigenically similar to A/Texas/50/2012, five showed reduced titers to A/Texas/50/2012 and 49 were antigenically similar to A/Switzerland/9715293/2013, which is the influenza A(H3N2) component recommended for the 2015 Southern Hemisphere influenza vaccine. Additionally, 250 A(H3N2) viruses were unable to be tested by HI assay; however, sequence analysis showed that 249 belonged to a genetic group that typically shows reduced titers to A/Texas/50/2012. Influenza A(H1N1): Two A(H1N1) viruses characterized were antigenically similar to A/California/7/2009. Influenza B: Of the 32 influenza B viruses characterized, 29 viruses were antigenically similar to B/Massachusetts/2/2012, and three viruses showed reduced titers (Figure 4).
Figure 4. Influenza strain characterizations, Canada, 2014-2015, N = 89
The NML receives a proportion of the number of influenza positive specimens from provincial laboratories for strain characterization and antiviral resistance testing. Characterization data reflect the results of haemagglutination inhibition (HAI) testing compared to the reference influenza strains recommended by WHO.
The recommended components for the 2014-2015 northern hemisphere trivalent influenza vaccine include: an A/California/7/2009(H1N1)pdm09-like virus, an A/Texas/50/2012 (H3N2)-like virus, and a B/Massachusetts/2/2012-like virus (Yamagata lineage). For quadrivalent vaccines, the addition of a B/Brisbane/60/2008-like virus is recommended.
Text equivalent for figure 4Influenza strain characterizations, Canada, 2013-2014, N =3
Influenza-like Illness (ILI) Consultation Rate
The national influenza-like-illness (ILI) consultation decreased in week 01 to 50.1 consultations per 1,000, which is above expected levels for week 01 (Figure 5). The rates were highest among the 0 to 4 years of age group (269.8 consultations per 1,000) and lowest among the adults ≥65 years of age (12.0 consultations per 1,000).
Figure 5. Influenza-like-illness (ILI) consultation rates by report week, compared to the 1996-97 through to 2012-13 seasons (with pandemic data suppressed), Canada, 2014-2015
Note: No data available for mean rate for weeks 19 to 39 for the 1996-1997 through 2002-2003 seasons. Delays in the reporting of data may cause data to change retrospectively. The calculation of the average ILI consultation rate over 17 seasons was aligned with influenza activity in each season. In BC, AB, and SK, data is compiled by a provincial sentinel surveillance program for reporting to FluWatch. Not all sentinel physicians report every week.
Text equivalent for figure 5Influenza-like-illness (ILI) consultation rates by report week, compared to the 1996-97 through to 2012-13 seasons (with pandemic data suppressed), Canada, 2013-2014
Influenza Outbreak Surveillance
In week 01, 195 new outbreaks of influenza were reported: 152 in long-term care facilities (LTCF), 12 in hospitals and 31 in institutional or community settings (Figure 6). Among the outbreaks in which the influenza subtype was known, two LTCF outbreaks and four institutional or community setting outbreaks were associated with A(H3N2). To date this season, 623 outbreaks in LTCFs have been reported. The number of outbreaks reported since week 47 is above those of previous seasons and is similar to the numbers reported during the 2012-13 influenza season when influenza A(H3N2) also predominated. The majority of the outbreaks with known subtypes are attributable to A(H3N2).
Figure 6. Overall number of new influenza outbreaks by report week, Canada, 2014-2015
1 All provinces and territories except NU report 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.
Text equivalent for figure 6Overall number of new influenza outbreaks by report week, Canada, 2013-2014
Pharmacy Surveillance
During week 01, the proportion of prescriptions for antivirals decreased to 918.5 antiviral prescriptions per 100,000 total prescriptions (down from 969.6 per 100,000 total prescriptions). The rate for antivirals since week 48 has been higher than the previous three seasons (Figure 7). The rate in age groups except children decreased in week 01. The antiviral prescription rate remains the highest amongst seniors at 1,552.8 per 100,000 total prescriptions.
Figure 7. Proportion of prescription sales for influenza antivirals by age-group and week, Canada, 2014-15
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 and Relenza) and the total number of new prescriptions dispensed by Province/Territory and age group. Age-groups: Infant: 0-2y, Child: 2-18y; Adult: 19-64y, Senior: ≥65y.
Text equivalent for figure 7Proportion of prescription sales for influenza antivirals by age-group and week, Canada, 2013-14
Sentinel Hospital Influenza Surveillance
Paediatric Influenza Hospitalizations and Deaths (IMPACT)
In week 01, 44 laboratory-confirmed influenza-associated paediatric (≤16 years of age) hospitalizations were reported by the Immunization Monitoring Program Active (IMPACT) network: 41 cases of influenza A and one case of influenza B(Figure 8a). Among the reported cases, 21 (48%) were <2 years of age, 19 (43%) were 2 to 9 years of age and 4 (9%) were 10-16 years of age. Four cases were admitted to the ICU. To date this season, 358 hospitalizations have been reported by the IMPACT network, 337 (94%) of which were cases of influenza A. Among cases for which the influenza A subtype was reported, 98% (127/129) were A(H3N2). Children <5 years of age represented 61% of cases (Table 4). To date, 38 cases were admitted to the ICU, of which 22 (58%) were 2 to 9 years of age (Figure 9a).
Note: The number of hospitalizations reported through IMPACT represents a subset of all influenza-associated paediatric hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
Adult Influenza Hospitalizations and Deaths (PCIRN)
In week 01, 106 laboratory-confirmed influenza-associated adult (≥16 years of age) hospitalizations were reported by the PHAC/CIHR Influenza Research Network (PCIRN) Serious Outcomes Surveillance (SOS) network, compared to 137 in week 53. Among cases in week 01, 96 cases (91%) were in adults over the age of 65 and 105 cases (99%) had influenza A (Figure 8b). To date this season, 672 cases have been reported; 664 (99%) with influenza A. The majority of cases (85%) were among adults ≥65 years of age (Table 5). Forty ICU admissions have been reported and the majority of cases (75%) were adults ≥65 years of age, most (69%) with known underlying conditions or comorbidities. Twenty-six deaths have been reported, all but three were adults >65 years of age (Figure 9b).
Note: The number of hospitalizations reported through PCIRN represents a subset of all influenza-associated adult hospitalizations in Canada. Delays in the reporting of data may cause data to change retrospectively.
Total | # (%) | |||||
1 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections. UnS: unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available. |
||||||
42 | 0 | 13 | 29 | 2 | 44 (12.3%) | |
78 | 1 | 25 | 52 | 8 | 86 (24.0%) | |
87 | 1 | 34 | 52 | 4 | 91 (25.4%) | |
85 | 0 | 35 | 50 | 5 | 90 (25.1%) | |
45 | 0 | 20 | 25 | 2 | 47 (13.1%) | |
337 | 2 | 127 | 208 | 21 | 358 | |
94.1% | 0.6% | 37.7% | 61.7% | 5.9% | 100.0% |
Total | # (%) | |||||
1 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections. UnS: unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available. |
||||||
3 | 0 | 0 | 3 | 0 | 3(%) | |
38 | 0 | 10 | 28 | 0 | 38(6%) | |
63 | 0 | 21 | 42 | 0 | 63(9%) | |
560 | 2 | 131 | 427 | 8 | 568(85%) | |
664 | 2 | 162 | 500 | 8 | 672 | |
99% | 0% | 24% | 75% | 1% | 100% |
A) Paediatric hospitalizations (≤16 years of age, IMPACT)
Text equivalent for figure 8aNumber of cases of influenza reported by sentinel hospital networks, by week, Canada, 2013-14: Paediatric hospitalizations (≤16 years of age, IMPACT)
B) Adult hospitalizations (≥16 year of age, PCIRN-SOS)
* See footnote above following the section related to PCIRN-SOS data.
Text equivalent for figure 8bNumber of cases of influenza reported by sentinel hospital networks, by week, Canada, 2013-14: Adult hospitalizations (>16 year of age, PCIRN-SOS)
Figure 9 - Percentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada, 2014-15
A) Paediatric hospitalizations (≤16 years of age, IMPACT)
Text equivalent for figure 9aPercentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada, 2013-14: Paediatric hospitalizations (≤16 years of age, IMPACT)
B) Adult hospitalizations (≥16 year of age, PCIRN-SOS)
Text equivalent for figure 9bPercentage of hospitalizations, ICU admissions and deaths with influenza reported by age-group, Canada, 2013-14: Adult hospitalizations (≥16 year of age, PCIRN-SOS)
Provincial/Territorial Influenza Hospitalizations and Deaths
In week 01, 566 laboratory-confirmed influenza-associated hospitalizations were reported from participating provinces and territories*; all but eight with influenza A, and 79% were patients ≥65 years of age. Since the start of the 2014-15 season, 2161 hospitalizations have been reported; 2121 (98%) with influenza A. Among cases for which the subtype of influenza A was reported, 99.6% (914/917) were A(H3N2). The majority of cases (69%) were ≥65 years of age (Table 6). Sixty two ICU admissions have been reported in adults ≥65 years of age with influenza A and 34 ICU admissions have been reported in adults 20-64 years. A total of 125 deaths have been reported since the start of the season: one child <5 years of age, one child 5-19 years, six adults 20-64 years, and 117 adults ≥65 years of age. Adults 65 years of age or older represent 94% of all deaths reported this season. Detailed clinical information (e.g. underlying medical conditions) is not known for these cases.
* Note: Influenza-associated hospitalizations are not reported to PHAC by the following Provinces and Territory: BC, NU, QC, and NB. Only hospitalizations that require intensive medical care are reported by Saskatchewan. ICU admissions are not distinguished among hospital admissions reported from Ontario. Data may also include cases reported by the IMPACT and PCIRN networks. The number of new influenza-associated hospitalizations and deaths reported for the current week may include cases from Ontario 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.
Total | # (%) | ||||||
1 Percentage of tests positive for sub-types of influenza A are a percentage of all influenza A detections. UnS: unsubtyped: The specimen was typed as influenza A, but no result for subtyping was available. |
|||||||
175 | 1 | 74 | 100 | 3 | 178 (8%) | ||
115 | 0 | 67 | 48 | 2 | 117 (5%) | ||
117 | 1 | 56 | 60 | 5 | 122 (6%) | ||
226 | 1 | 109 | 116 | 5 | 231 (11%) | ||
1471 | 0 | 591 | 880 | 24 | 1495 (69%) | ||
17 | 0 | 17 | 0 | 1 | 18 (1%) | ||
2121 | 3 | 914 | 1204 | 40 | 2161 | ||
97.4% | 0.3% | 70.3% | 29.4% | 2.6% | 100.0% |
...
http://www.phac-aspc.gc.ca/fluwatch/.../index-eng.php
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