Tiny tweaks helped flu strains thwart 2014-2015 vaccine


Changes to the flu strains circulating around the Northern Hemisphere explain why last year’s flu vaccine didn’t work so well.

Judy Schmidt/CDC(CC0 1.0)

Last year’s flu vaccine was a dud, and now scientists know why.

The vaccine targeted a flu strain that didn’t look like most of the strains traveling around the Northern Hemisphere during the 2014-2015 flu season, researchers report June 25 in Cell Reports.

Like wearing a hat and glasses or a fake mustache, tiny changes to the strains’ appearance let the virus disguise itself from the immune systems of vaccinated people. The finding explains the U.S. Centers for Disease Control and Prevention’s lackluster estimate of the vaccine’s efficiency: It was only about 20 percent effective at preventing flu-related trips to the doctor.

The new finding will help researchers formulate better vaccines for future flu seasons, the study’s authors conclude. 

Meghan Rosen headhsot

Meghan Rosen is a staff writer who reports on the life sciences for Science News. She earned a Ph.D. in biochemistry and molecular biology with an emphasis in biotechnology from the University of California, Davis, and later graduated from the science communication program at UC Santa Cruz.

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