India is among 140 countries that rely on the oral polio vaccine. For India, which has successfully kept naturally-occurring ‘wild’ polioviruses at bay for three whole years, a new challenge looms. India is among 140 countries that rely on the oral polio vaccine (OPV). These countries have now been asked to introduce an injectable inactivated polio vaccine (IPV) into their routine childhood immunisation programme by the end of next year.