The flu vaccine is only 10 percent effective this year

Posted at 11:33 AM, Feb 02, 2018

The first data on how well the flu vaccine is working this season in North America has just been published.

The main flu subtype going around in the U.S. and Canada this season is H3N2. A recent study from the journal Eurosurveillance, Europe's journal on infectious disease surveillance, found that the vaccine in use this season is only 10 percent effective.

To produce flu vaccines, manufacturers must grow flu viruses. Researchers discovered long ago that a flu virus grows extremely effectively in eggs. However, researchers also found that there are problems with the egg-based approach that specifically relate to H3N2, and those issues are contributing to lower efficacy this season.

Supplement 1: GISAID sequences used in the study