>>14099588This screenshot is a crock of shit.
Paralytic poliomyelitis outbreaks occurred precisely in areas with great sanitation as later exposure in childhood is associated with more severe illness(
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4108111/ )
Salk Polio vaccinations began en masse in 1955 after which polyomyelitis cases declined to almost nothing (
https://ourworldindata.org/polio ). From the early 20th century onward, the US had seen a sharp increase in paralytic polio cases. It wasn't "erradicated" in urban areas as that post claims.
This was the Salk vaccine, which was 60-70% effective vs type 1 poliovirus but aside from a single incident of poor preparation by a laboratory (Cutler incident) had virtually nil chance of reactivation. Sabin came up with the oral polio vaccine which was a lot more effective in reducing cases because of how it generates immunity but carries a small risk of becoming active. When cases in the US were down to virtually 0 for decades the CDC switched to recommending the less effective but less risky IPV (analogous to Salk's).
That wasn't the case until not long ago in shitholes abroad where wild type polio still existed. Policy is now changing in those places where wild type polio has been eliminated as well.
