What is OPV?
Two types of polio vaccine are available: oral polio vaccine (OPV) and inactivated polio vaccine (IPV). OPV was developed by Albert Sabin, and first licensed in 1962. OPV is made with a live but weakened (attenuated) virus and is administered through the mouth, usually by a dropper, thus it is called an oral vaccine. The weakened virus provokes immunity in the human body, but is too weak to cause disease, thus protecting people from future contract with wild (disease causeing) poliovirus. OPV protects vaccinated persons directly and also protects other susceptible persons who are indirectly “vaccinated” as the vaccine virus spreads in the community. IPV is given by injection and protects vaccinated persons as well as OPV, but it is not believed to be as effective as OPV in preventing the spread of polio virus among non-vaccinated persons.
