A group of Canadian researchers has published data suggesting a mismatch between the formulation of the influenza vaccine this year and the dominant emerging flu strain infecting people. CIDRAP has the news.
Complicating the issue is the fact that the CDC has “not posted the standard weekly respiratory illness surveillance data since September 26, and it is unknown when or if national surveillance in the country will resume.” The H3N2 subclade K was represented in 90% of flu samples in early data from the United Kingdom and Japan. Subclade J and J.2 were used as vaccine reference strains for this year’s shot.
The researchers who published the data say that they “do not believe this strain of H3N2 will lead to a pandemic.” The lead researcher, Danuta Skowronski, also said she was encouraged because “the mutation sites would not affect how well antiviral drugs work, and the mutations are not associated with increased virulence or severity.” However, more flu cases should be expected “if vaccine efficacy is significantly reduced.”
Another expert said that “H3N2-dominant seasons pack a bigger punch, with lower effectiveness of the vaccine and more severe illness in older adults than in H1N1-dominant years.” Uptake on the flu vaccine is still important, as it can continue to help prevent severe illness even with a mismatch.
