CALGARY- While over a million Albertans have already rolled up their sleeves for flu shot this season, new research suggests this year’s vaccine may not be all that effective.
A new study by the Centre for Disease Control (CDC) found as many as 50% of those who get the shot may not be protected from the most common strain of the illness in circulation this year.
“The most common strain we’re seeing right now, all over the country, is the H3N2 virus,” said Dr. Joe Bresee with the CDC. “Only about half of those viruses are like the vaccine. About half of those viruses look different than the vaccine right now.”
This year’s flu vaccine protects against two strains of influenza A: H1N1 and H3N2. It also protects against one strain of influenza B.
The CDC report reveals the type of H3N2 virus circulating this year is different from the one that was used to make this year’s flu shot.
“The virus we use to make the vaccine has changed so the vaccine makers are working on trying to get a better match so we can get a more effective vaccine,” said Dr. James Dickinson, head of the Alberta Influenza Surveillance Program. “But unfortunately, that’s not ready for this year.”
Every year, the World Health Organization predicts what strains will be most active in the season ahead and then manufacturers spend the next 6 months preparing the vaccine. Canadian researchers then track how effective that vaccine really is. Last season, when H1N1 was a dominant strain, the flu shot was about 75% effective.
There have now been 9 flu-related deaths across Alberta this season. Two of those deaths occurred in Calgary. Meanwhile, 578 cases of the flu have been confirmed across the province.