Influenza vaccine efficacy

I am writing in response to a recent news article¹ published in CMAJ. The lack of efficacy of this year’s vaccine preparation is often used as an argument against vaccination. Although the match between the vaccine H3N2 strain and the circulating H3N2 wild-type may not be optimum, we must recognize that influenza seasons often have two strains. In addition to the recent H3N2 epidemic activity in Canada, we will likely see a second (and unpredictable) wave, such as influenza B, this season. Therefore, the efficacy of the 2014–2015 vaccine will only be fully measurable at the end of May, 2015.