Experts call this a coincidence.
"Cases of polio within 10 days of vaccination were classified as 'unvaccinated,' and the definition of polio itself was rewritten to make the vaccine look more effective."
https://blossom.primal.net/59a3a9bd04c8de10670e6b75ea8db303ed9cdb59a400eeea2d15f6eb8d27932e.mp4