Regarding the flu shot: If you're at risk of not surviving the flu because your immune system is weakened, you might also not be gaining much protection from the flu shot, even in years where they got lucky with the target selection. But those same people *do* benefit if the healthy people around them are less likely to infect them. So you'd have to compare death rates at nursing homes where the staff is vaccinated vs not vaccinated. Might be tricky to get an IRB to sign off on that study though 😬

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Yeah, but it's not clear that vaccinated/unvaccinated makes any difference in transmission. I don't think the paper clarifies the vaccination status of the workers (or visitors) but presumably if the shots to the patients were randomized, that wouldn't matter.

Whenever I study the evidence for flu shots, I come away realizing the efficacy is surprisingly questionable. Something like Vitamin D supplementation seems to have at least (maybe more) effect and I wonder why that doesn't get as much attention.

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