According to data from Canada, the current flu vaccine is 72% effective against H1N1, which is the predominant strain of influenza this season, Healio.com reports.
To estimate vaccine effectiveness in Canada, researchers assessed 1,518 eligible specimens collected from patients aged 1 year or older. Overall, 44% tested positive for influenza, of which 99% were influenza A. Of the samples subtyped as influenza A, 93% were H1N1 and 7% were H3N2.
Researchers calculated that the vaccine was 68% (95% CI, 55-77) effective against any influenza virus and 72% (95% CI, 60-81) effective against H1N1.