The CDC admitted that between 1055 & 1963, over 98 million Americans one or more doses of Polio shot that was contaminated with a virus causing cancer called Simian Vacuolating Virus 40 (SV40), seems like a anti vaxer scare tactic. Although the US gov., does a bunch they never really tell us. https://www.nytimes.com/2002/10/23/us/study-is-unsure-on-tainted-polio-vaccine-s-cancer-role.html my mom does have a tumor on her head & I think she got the shot. She went to a Dermatologist, but they said don't worry. Not thinking they would really know. The Covid thing is a big worry though, so we try to stay home. Hopefully Biden will care about getting cases down.