Polio provocation (from other vaccines) was well understood 60 years ago.

"Several ideas were posited by health professionals in an effort to understand how immunisations for diphtheria, tetanus, and pertussis seemed to provoke polio infection. One theorist posited that injections injured human tissues and predisposed them to viral infection. A further theory advanced by Harold K Faber of the Stanford University School of Medicine argued that the ubiquitous poliovirus, already present on the skin of many children, was being driven into the body during immunisations and thus seeded deep into the tissue. The lack of certainty heightened anxiety and brought the issue to mainstream attention."

"In 1998, State University of New York researchers Matthias Gromeier and Eckard Wimmer published a pioneering article on the mechanism of injection-induced polio paralysis. Through their laboratory work, they discovered that tissue injury produced by an injection aided the poliovirus to infect the body and readily journey to the spinal cord. For the first time, health professionals working in polio endemic regions had scientific evidence that paediatric injections could incite paralysis."

Amazing how they forget what they don't want us to know.

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)61251-4/fulltext?rss=yes