History of Poliomyelitis - Vaccine Development

Vaccine Development

In 1935 Maurice Brodie, a research assistant at New York University, attempted to produce a polio vaccine, procured from virus in ground up monkey spinal cords, and killed by formaldehyde. Brodie first tested the vaccine on himself and several of his assistants. He then gave the vaccine to three thousand children, many developed allergic reactions, but none of the children developed an immunity to polio. During the late 1940s and early 1950s, a research group, headed by John Enders at the Boston Children's Hospital, successfully cultivated the poliovirus in human tissue. This significant breakthrough ultimately allowed for the development of the polio vaccines. Enders and his colleagues, Thomas H. Weller and Frederick C. Robbins, were recognized for their labors with the Nobel Prize in 1954.

Two vaccines are used throughout the world to combat polio. The first was developed by Jonas Salk, first tested in 1952, and announced to the world by Salk on April 12, 1955. The Salk vaccine, or inactivated poliovirus vaccine (IPV), consists of an injected dose of killed poliovirus. In 1954, the vaccine was tested for its ability to prevent polio; the field trials involving the Salk vaccine would grow to be the largest medical experiment in history. Immediately following licensing, vaccination campaigns were launched, by 1957, following mass immunizations promoted by the March of Dimes the annual number of polio cases in the United States would be dramatically reduced, from a peak of nearly 58,000 cases, to just 5,600 cases.

Eight years after Salk's success, Albert Sabin developed an oral polio vaccine (OPV) using live but weakened (attenuated) virus. Human trials of Sabin's vaccine began in 1957 and it was licensed in 1962. Following the development of oral polio vaccine, a second wave of mass immunizations would lead to a further decline in the number of cases: by 1961, only 161 cases were recorded in the United States. The last cases of paralytic poliomyelitis caused by endemic transmission of poliovirus in the United States were in 1979, when an outbreak occurred among the Amish in several Midwestern states.