Or variants emerging from those vaccinated. It’s nonsense to assume “the unvaccinated are dirty Petri dishes where mutations come from!” Variants can come from vaccines themselves or mutating in the host and then spreading.
If anyone think that’s impossible, such a phenomenon is happening right now in Africa with Polio. Wild Polio is declared to be eradicated. A vaccine derived strain is keeping the outbreak alive.
Sure, it can happen, and viruses spread even through a vaccinated population, but quantity is a quality all of its own. Vaccinate everyone, and the number of opportunities for the virus to mutate and spread drops by orders of magnitude. Vaccinate half the population, and all that you'll do is create a great amount of evolutionary selection pressure for a mutation.
If anyone think that’s impossible, such a phenomenon is happening right now in Africa with Polio. Wild Polio is declared to be eradicated. A vaccine derived strain is keeping the outbreak alive.
https://www.npr.org/sections/goatsandsoda/2020/08/25/9058847...