Why is the flu vaccine so mediocre?
Jon Cohen
Science 22 Sep 2017:
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Summary
With flu season around the corner in the United States and Europe, the push has begun once again to encourage people to receive their annual shots. But over the past few years, it's become increasingly clear that the level of protection offered by the vaccine varies widely each flu season, from 10% to 60%. And new research has revealed surprising reasons for its lackluster performance. For decades, it appeared that the vaccine had an efficacy of 70% to 90%, but scientists now know that's because they were using a misleading test—replaced in the 1990s—to assess whether it protected people.
http://science.sciencemag.org/content/357/6357/1222
