As a response, a novel oral polio vaccine type 2 (nOPV2) was developed with the aim to provide a safer form of vaccination against type 2 strains with less risk of reverting to infectious polio. Schedule
In countries with endemic polio or where the risk of imported cases is high, the WHO recommends OPV vaccine at birth followed by a primary series of three OPV doses and at least one IPV dose starting at 6 weeks of age, with a minimum of 4 weeks between OPV doses. In countries with >90% immunization coverage and low risk of importation, the WHO recommends one or two IPV doses starting at 2 months of age followed by at least two OPV doses, with the doses separated by 4–8 weeks depending on the risk of exposure. In countries with the highest levels of coverage and the lowest risks of importation and transmission, the WHO recommends a primary series of three IPV injections, with a booster dose after an interval of six months or more if the first dose was administered before 2 months of age. Side effects
The inactivated polio vaccines are very safe. Mild redness or pain may occur at the site of injection. Oral polio vaccine results in vaccine-associated paralytic poliomyelitis in about three per million doses. They are generally safe to give to those who are pregnant, and those who have HIV/AIDS, but who are otherwise well.
Jonas Salk
The first effective polio vaccine was developed in 1952 by Jonas Salk and a team at the University of Pittsburgh that included Julius Youngner, Byron Bennett, L. James Lewis, and Lorraine Friedman, which required years of subsequent testing. Salk went on CBS radio to report a successful test on a small group of adults and children on 26 March 1953; two days later, the results were published in JAMA. Leone N. Farrell invented a key laboratory technique that enabled the mass production of the vaccine by a team she led in Toronto. Beginning 23 February 1954, the vaccine was tested at Arsenal Elementary School and the Watson Home for Children in Pittsburgh, Pennsylvania.Salks vaccine was then used in a test called the Francis Field Trial, led by Thomas Francis, the largest medical experiment in history at that time. The test began with about 4,000 children at Franklin Sherman Elementary School in McLean, Virginia, and eventually involved 1.8 million children, in 44 states from Maine to California. By the conclusion of the study, roughly 440,000 received one or more injections of the vaccine, about 210,000 children received a placebo, consisting of harmless culture media, and 1.2 million children received no vaccination and served as a control group, who would then be observed to see if any contracted polio.The results of the field trial were announced 12 April 1955 (the tenth anniversary of the death of President Franklin D. Roosevelt, whose paralytic illness was generally believed to have been caused by polio).