SV40 was a contaminant in the polio vaccines in the 50s and 60s. They knew it was in the batches, they just didn’t want to spend time and money to take it out. People wonder why cancer rates skyrocketed since then.
It’s true, and there is also a tie in to Lee Harvey Oswald and his girlfriend at the time. Great book “Dr Marys Monkeys”. There was a lot going on in the late 50’s early 60’s in Lose E Anna. There were trying to weaponize cancer to kill Castro, and it is researchable. If I weren’t so blessed old, I could cite references from my memory.