I'm flabbergasted here. This isn't a correct interpretation of vaccine efficacy—and that 95% number. It doesn't mean vaccines leave 1 in 20 people "unprotected". https://www.timesnews.net/living/wellness/5-reasons-to-wear-a-mask-even-after-you-re-vaccinated/article_382fb8e0-5bfc-11eb-9945-2315e7061dc1.html

I also personally disagree that "masks and distancing" are here to stay, at least in their current form, "until herd immunity"—we will likely get relaxations and new guidelines, especially for private behavior for vaccinated people depending on their risk levels long before that.

But at least that part is something to discuss! I hope we get a quick correction to the above quote, though. @LizSzabo

Correct. Vaccine efficacy is a relative measure. In the trials, it's a ratio among those who got symptomatic COVID—even if it was mild (which was the endpoint). It does not mean 1 in 20 unprotected. Whatever the source of error, correction needed. https://twitter.com/lyndon_bae_j/status/1361432394335735814

Pfizer vaccine efficacy calculation from their EUA. The vaccinated & vaccinated groups are ~identical in size, so we can just compare cases. Only 8 vaccinated got symptomatic COVID (almost all mild) compared to 162 among unvaccinated. That's the 95%; it compares relative risk.

Further, even if you were among the few who got symptomatic COVID after vaccination, it wasn't a case of being "unprotected"—there were no deaths, no hospitalizations among the vaccinated and the single "severe" case was borderline Sp02 93% and she needed no medical attention.

In sum: 95% efficacy does not mean that 5% in the vaccine group got infected (not at all! Not even close! It was .04% for Pfizer trial) or that those who had symptomatic COVID despite vaccine were "unprotected": no greatly reduced severity, no hospitalization, no death.