There are reasons why drug approval can be slow and conservative: https://en.wikipedia.org/wiki/Thalidomide_scandal
For example 780,000 people died of polio between 1988 and today. Yet for all that time there has been a cheap, low risk, well tested, near 100% effective vaccine (many in fact). And polio is probably one of the better cases because governments and charities have been pushing it pretty hard.
Edit: Also, polio eradication efforts where a Manhattan project style heroic effort.