[asynchronous]

Almost makes it sound like we would have eradicated polio had we not revived with with oral vaccines.

[gus_massa]

The injectable polio vaccine does not stop the transmission. It only make the virus not attack the nervous system, so you don't get paralysis. This is good, but it's impossible to erradícate polio with it.

Once a country has no polio cases for a long enough time, they switch to only injectable version. More details in https://en.wikipedia.org/wiki/Polio_vaccine#Schedule