# 4057
The Public Health Agency of Canada produces a weekly influenza summary called FluWatch, which is very similar to the US FluView report from the CDC. In it you will find maps, charts, and summaries of the previous week’s influenza surveillance.
As in the United States, Canada is in the midst of a serious outbreak of influenza, more befitting of what might be expected in January or February than mid November.
A few excerpts from this week’s report (ending Nov 14th), but follow the FluWatch link to read it in its entirety.
Summary of FluWatch Findings for the
Week ending November 14, 2009
- Nationally, the activity level reported this week remained similar to the previous week. While the number of hospitalizations and deaths still increased, the proportion of positive influenza tests was comparable and the national ILI consultation rate and the number of influenza outbreaks reported decreased.
- The Pandemic (H1N1) 2009 strain accounted for nearly 100% of the positive influenza A subtyped specimens this week.
- The intensity of Pandemic (H1N1) 2009 in the population was high with 1,674 hospitalizations, 261 ICU admissions and 84 deaths reported this week. Hospitalized cases occurred in all provinces and territories (P/T) that reported this week while the deaths were from all P/T except MB, PE, YT, NT and NU. From August 30 to November 14, 2009, a total of 3,965 hospitalized cases including 576 cases admitted to an intensive care unit (ICU) (14.5%) as well as 142 deaths had been reported. Numbers of new deaths were more than two times higher than last week.
- The number of hospitalizations and deaths reported this week were higher than the overall number of hospitalizations and deaths for the first wave.
- While the proportion of severe cases (ICU admissions and deaths) among all hospitalized cases was lower in previous weeks, the proportion of deaths over all hospitalized (5%) this week is back to what was observed in the first wave.
Overall Influenza Summary - Week 45 (November 8 to November 14, 2009)
Nationally, the overall activity level reported this week remained similar to the previous week. While the number of hospitalizations and deaths still increased, the proportion of positive influenza tests was comparable and the national ILI consultation rate and the number of influenza outbreaks reported decreased.
Canadian situation
Antigenic Characterization
Since September 1, 2009, NML has antigenically characterized 218 Pandemic (H1N1) 2009 viruses and three seasonal influenza viruses (one influenza A/H1N1, one influenza A/H3N2 and one B virus) that were received from Canadian laboratories. All 218 Pandemic influenza A (H1N1) viruses characterized were antigenically related to A/California/7/2009, which is the pandemic reference virus selected by WHO as Pandemic (H1N1) 2009 vaccine. The one seasonal influenza A/H1N1 virus characterized was related to A/Brisbane/59/07, the one seasonal influenza A (H3N2) virus characterized was related to A/Brisbane/10/07 and the one influenza B virus characterized was antigenically related to B/Brisbane/60/08, which are the components recommended for the 2009-10 influenza vaccine.
Antiviral Resistance
NML: Pandemic (H1N1) 2009 viruses tested so far have been sensitive to zanamivir (114 samples) but resistant to amantadine (84 samples). Of the 125 Pandemic (H1N1) 2009 viruses tested, 122 were sensitive to oseltamivir and three viruses were resistant to oseltamivir with the H275Y mutation. The three resistant cases, 2 from Ontario and 1 from Quebec, were associated with oseltamivir treatment.
Provinces: Three cases of oseltamivir resistant Pandemic (H1N1) 2009 were reported to date in Canada from the province of Quebec on July 21, 2009, from Alberta on September 15, 2009 and from Ontario on October 13, 2009.
Vaccine Coverage and Safety
As of November 7, 2009, a total of 6.6 million doses of Pandemic (H1N1) 2009 vaccine were distributed. 634 adverse events and 36 serious adverse events were reported from October 21 to November 7, 2009. The most frequently reported events were minor and included nausea, dizziness, headache, fever, vomiting and injection site reactions.The 36 serious adverse events included several reports of febrile seizures and anaphylaxis. One of the reported cases of anaphylaxis has been fatal and is being investigated. No unadjuvanted vaccine was administered during this time period as it was not delivered to provinces and territories until November 8, 2009.
