Surprised that I'm getting this question. But no, vaccines do not offer a guarantee of safety. They vastly reduce your probability of symptoms, hospitalization, and death. We should not be surprised when the occasional vaccinated person still ends up in hospital. (Thread) [1/6]

Though efficacy was seen to be very high, each COVID vaccine nonetheless has a small probability of failure. A handful of people will not produce sufficient antibodies to neutralize incoming virus. [2/6]

So if such a person (with a failed vaccine response) were exposed to the virus, the risk of infection, and therefore of hospitalization, will be comparable to that of an unvaccinated person. [3/6]

The probability of being exposed to the virus is high when the community prevalence is high. This is why vaccinated people should wear masks and distance while incidence rates remain high... they might be among the few who can still become infected and transmit. [4/6]

But as more people become vaccinated, the community transmission levels will fall. Incidence rates will plummet. So the probability of encountering the virus will also fall. When that happens, even the people for whom the vaccine failed will be protected. [5/6]

Takeaways: (1) a very small number of vaccinated people will still get sick and might be hospitalized; (2) so even the vaccinated have to respect public health guidance; (3) but only until enough people are jabbed and incident rates plummet. [6/6]