The oral polio vaccine (OPV) contains live-attenuated polioviruses that induce immunity by causing low virulence infections in vaccine recipients and their close contacts. Widespread immunization with OPV has reduced the annual global burden of paralytic poliomyelitis by a factor of 10. 000 or more and has driven wild poliovirus (WPV) to the brink of eradication. However. https://www.hindigyanvishv.com/