“One of the most common reasons given for mass COVID vaccinations is the idea that if we reach herd immunity through vaccination, we can starve the virus out of existence and get our lives back. It's the COVID-Zero strategy or some variant of it. By now it is abundantly clear from the epidemiological data that the vaccinated are able to both catch and spread the disease. Clearly, vaccination isn't going to make this virus disappear. Only a mind that has lost its grasp on reality can fail to see how ridiculous all this has become.”
This is a long but worthwhile read. Mentioned in the article is Marek's Disease which has not been mentioned much, even by the conspiracy theorists. Will the Marek Effect Happen? We have no idea. But why should we be risking it?
There is a good article on Marek's disease in National Geographic from 2015 and a good summary in Wikipedia. See the first Comment for links.