The polio vaccine actually went to the inactive form to reduce the risk of polio from one of the vaccine strains reverting to wild type and infecting others. It is still less effective at achieving herd immunity than the live version because of the lack of viral spread.
The polio vaccine actually went to the inactive form to reduce the risk of polio from one of the vaccine strains reverting to wild type and infecting others. It is still less effective at achieving herd immunity than the live version because of the lack of viral spread.