British Columbia Influenza Surveillance Bulletin
Influenza Season 2013-14, Number 07, Weeks 51-52
December 15 to December 28, 2013
Ongoing, increased influenza activity in BC, predominantly A(H1N1)pdm09
In weeks 51-52 (December 15 to 28, 2013), influenza activity increased in BC. Influenza A(H1N1)pdm09continues to be the predominant circulating strain, representing 51/61 (83.6%) of specimens with subtype information available during weeks 51-52. The proportion of respiratory specimens testing positive for influenza increased sharply from 17.3% in week 50 to 25.6% in week 51 and 42.5% in week 52. The BC Medical Services Plan (MSP) claims for influenza illness as a proportion of all claims increased throughout the province and were above 10-year maximum values. The proportion of patients with influenza-like illness among those presenting to sentinel physicians and the consultation rates attributed to ILI at BC Children?s Hospital ER also increased significantly during this period after remaining stable for the past few weeks. Consistency across surveillance indicators suggests a real increase in influenza activity in BC, but may also reflect differences in health care seeking behaviours during the holiday period. Ongoing monitoring is required in the coming weeks.
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In weeks 51-52, the proportion of patients with influenza-like illness (ILI) among those presenting to sentinel physicians increased from ≤0.2% in weeks 48-50 to 0.31% in week 51 and 0.52% in week 52. Consultation rates exceeded the historical average in week 52 but remained within the expected range for this time of year. Only 45% and 29% of sentinel sites reported data to date for weeks 51 and 52, respectively. Rates are subject to change as data become more complete following the holiday period.
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In weeks 51-52, the proportion of visits to BC Children?s Hospital Emergency Room (ER) attributed to ILI increased sharply from ≤11% in weeks 48-50 to 15.6% in week 51 and 21.3% in week 52. Rates were slightly above past seasons for this time of year but comparable to the 2012-13 season.
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To date since week 40 (September 29 ? October 5, 2013), 203 specimens have tested positive for influenza at the BC Public Health Microbiology & Reference Laboratory (PHMRL). Of the 131/203 specimens with subtype information available, 110 (84.0%) were influenza A(H1N1)pdm09, 8 (6.1%) were influenza A(H3N2), and 13 (9.9%) were influenza B. The majority of these detections (133/203 or 65.5%) have occurred in weeks 51-52.
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In weeks 51-52, 380 specimens (168 in week 51 and 212 in week 52) were tested for influenza at the BC PHMRL. In week 51, 43 (25.6%) were positive for influenza [39 A(H1N1)pdm09, 1 A(H3N2), 2 influenza B, and 1 influenza A (subtype pending)]. In week 52, 90 (42.5%) were positive for influenza [12 A(H1N1)pdm09, 3 A(H3N2), 4 influenza B, and 71 influenza A (subtype pending)]. The percent positivity continued to increase in both weeks compared to previous weeks from <5% in weeks 40-48, 10.6% in week 49 and 17.3% in week 50, to 25.6% in week 51 and 42.5% in week 52. As with previous weeks, influenza A(H1N1)pdm09 continued to predominate during this period. Of the 61 specimens with subtype information available, 51 (83.6%) were influenza A(H1N1)pdm09 in weeks 51-52.
Among other respiratory viruses, rhino/enteroviruses were the most commonly detected, followed by RSV during this period.
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Full report:
Influenza Season 2013-14, Number 07, Weeks 51-52
December 15 to December 28, 2013
Ongoing, increased influenza activity in BC, predominantly A(H1N1)pdm09
In weeks 51-52 (December 15 to 28, 2013), influenza activity increased in BC. Influenza A(H1N1)pdm09continues to be the predominant circulating strain, representing 51/61 (83.6%) of specimens with subtype information available during weeks 51-52. The proportion of respiratory specimens testing positive for influenza increased sharply from 17.3% in week 50 to 25.6% in week 51 and 42.5% in week 52. The BC Medical Services Plan (MSP) claims for influenza illness as a proportion of all claims increased throughout the province and were above 10-year maximum values. The proportion of patients with influenza-like illness among those presenting to sentinel physicians and the consultation rates attributed to ILI at BC Children?s Hospital ER also increased significantly during this period after remaining stable for the past few weeks. Consistency across surveillance indicators suggests a real increase in influenza activity in BC, but may also reflect differences in health care seeking behaviours during the holiday period. Ongoing monitoring is required in the coming weeks.
...
In weeks 51-52, the proportion of patients with influenza-like illness (ILI) among those presenting to sentinel physicians increased from ≤0.2% in weeks 48-50 to 0.31% in week 51 and 0.52% in week 52. Consultation rates exceeded the historical average in week 52 but remained within the expected range for this time of year. Only 45% and 29% of sentinel sites reported data to date for weeks 51 and 52, respectively. Rates are subject to change as data become more complete following the holiday period.
...
In weeks 51-52, the proportion of visits to BC Children?s Hospital Emergency Room (ER) attributed to ILI increased sharply from ≤11% in weeks 48-50 to 15.6% in week 51 and 21.3% in week 52. Rates were slightly above past seasons for this time of year but comparable to the 2012-13 season.
...
To date since week 40 (September 29 ? October 5, 2013), 203 specimens have tested positive for influenza at the BC Public Health Microbiology & Reference Laboratory (PHMRL). Of the 131/203 specimens with subtype information available, 110 (84.0%) were influenza A(H1N1)pdm09, 8 (6.1%) were influenza A(H3N2), and 13 (9.9%) were influenza B. The majority of these detections (133/203 or 65.5%) have occurred in weeks 51-52.
...
In weeks 51-52, 380 specimens (168 in week 51 and 212 in week 52) were tested for influenza at the BC PHMRL. In week 51, 43 (25.6%) were positive for influenza [39 A(H1N1)pdm09, 1 A(H3N2), 2 influenza B, and 1 influenza A (subtype pending)]. In week 52, 90 (42.5%) were positive for influenza [12 A(H1N1)pdm09, 3 A(H3N2), 4 influenza B, and 71 influenza A (subtype pending)]. The percent positivity continued to increase in both weeks compared to previous weeks from <5% in weeks 40-48, 10.6% in week 49 and 17.3% in week 50, to 25.6% in week 51 and 42.5% in week 52. As with previous weeks, influenza A(H1N1)pdm09 continued to predominate during this period. Of the 61 specimens with subtype information available, 51 (83.6%) were influenza A(H1N1)pdm09 in weeks 51-52.
Among other respiratory viruses, rhino/enteroviruses were the most commonly detected, followed by RSV during this period.
...
Full report:
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