A public health effort to permanently eliminate all cases of poliomyelitis (polio) infection around the world began in 1988, led by the World Health Organization (WHO), the United Nations Children's Fund (UNICEF) and the Rotary Foundation. These organizations, along with the U.S. Centers for Disease Control and Prevention (CDC) and The Gates Foundation, have spearheaded the campaign through the Global Polio Eradication Initiative (GPEI). Successful eradication of infectious diseases has been achieved twice before, with smallpox[2] and bovine rinderpest.
Prevention of disease spread is accomplished by vaccination. There are two kinds of polio vaccine—oral polio vaccine (OPV), which uses weakened poliovirus, and inactivated polio vaccine (IPV), which is injected. The OPV is less expensive and easier to administer, and can spread immunity beyond the person vaccinated, creating contact immunity. It has been the predominant vaccine used. However, under conditions of long-term vaccine virus circulation in under-vaccinated populations, mutations can reactivate the virus to produce a polio-inducing strain, while the OPV can also, in rare circumstances, induce polio or persistent asymptomatic infection in vaccinated individuals, particularly those who are immunodeficient. Being inactivated, the IPV is free of these risks but does not induce contact immunity. IPV is more costly and the logistics of delivery are more challenging.