Claim: 70% of polio cases today are caused by the polio vaccine.

Validity: True but misleading

That's why most of the polio today, 70% of the polio today is vaccine polio that came from the vaccines. So the regulators expressed a preference for dead virus vaccines.

-Joe Rogan Experience #1999 23:15

https://youtu.be/p6LJXPOv4SM?si=8007SL4KBaY5IFw1&t=1395

It does appear true that many if not most of the polio today is caused by the vaccine rather than wild cases. This paper outlines the impacts of so called vaccine-derived polioviruses (VDPV). But it also outlines the importance of continued vaccine usage to eliminate wild cases of polio. The high percentage of VDPV as discussed by the WHO is actually an indicator of the success of polio vaccines. Wild cases have been cut so dramatically that the proportion of VDPV becomes larger. According to the WHO:

Cases due to wild poliovirus have decreased by over 99% since 1988, from an estimated 350 000 cases in more than 125 endemic countries, to two endemic countries.

It is also noted in the paper that the oral vaccine is the primary culprit of VDPV. While it is less expensive and therefore a more accessible option to eliminate wild polio cases, there are options that present no risk of VDPV. The WHO has begun implementing new strategies to reduce the risk of VDPV in the future.