Isn't there usually at least a 1:100 or 1:1000 safety buffer between vaccination and control to make a vaccine safe? At least for other vaccines that's a common threshold.
The relative risk between potentially getting the disease even though the population is already highly herd immunized (compare e.g. measles) and the risk of the vaccine is still 1:1000. This means despite measles already being such a rare disease it is still a clear benefit to get vaccinated.
With a disease such as Covid it might be 100000x safer to get vaccinated than not.
All national vaccination programs must calculate and assess such relative risk and find so much advantage in favor of vaccination.
