The rollout of COVID-19 vaccines was far faster than Salk's polio vaccine. It was not used in lower income countries for quite a while, really until OPV came al

The rollout of COVID-19 vaccines was far faster than Salk's polio vaccine. It was not used in lower income countries for quite a while, really until OPV came along to really get going. The vaccine was made by multiple manufacturers in the US, including what is now Pfizer.