That's not true, and it's not true in a totally fascinating way. The flu shot is aimed towards a projected virus, based in part on last year's viruses, but also

That's not true, and it's not true in a totally fascinating way. The flu shot is aimed towards a projected virus, based in part on last year's viruses, but also on a host of other things. The nitty-gritty on it can be highly technical (and highly interesting, if you're into that sort of thing!), but here's a nice overview that should give the lay-person a broad idea of how it's done: https://www.cdc.gov/flu/professionals/laboratory/genetic-characterization.htm https://www.cdc.gov/flu/professionals/laboratory/genetic-cha...