Who Developed the Polio Vaccine?

Mass vaccination campaigns transformed poliomyelitis from a feared disease to a rarity. Two vaccines, each relying on groundbreaking research, were developed almost simultaneously. Together, they dramatically reduced the number of polio cases worldwide and eradicated the disease from industrialized countries.

Poliomyelitis

• Poliovirus enters the body through the mouth and settles in the intestines, where it multiplies and is shed in the feces. Once established, poliovirus enters the bloodstream and crosses into the central nervous system, where it damages nerve cells. With a lack of nerve impulses, the affected muscles cannot function.

  Arms and legs are affected first, but the chest muscles can become involved in more severe cases, leading to respiratory distress. Paralysis is an uncommon symptom. Most infected people show no signs or only mild symptoms such as nausea, headache, fatigue, neck stiffness, fever or pain in the arms and legs. Polio has no cure and cannot be prevented except through vaccination, according to the Global Polio Eradication Initiative.

Early Polio Vaccine Research

• Sweeping polio epidemics underscored the need for a preventive vaccine. Dr. Albert B. Sabin of the Children's Hospital Research Foundation in Cincinnati, Ohio, conducted the first steps toward vaccine development in 1939. Sabin demonstrated that although poliovirus affects the nerves, it resides in the intestines. This finding proved polio was a virus of the gut, not the nervous system, and might therefore be prevented by an oral vaccine.

  Before Sabin could pursue his theory, World War II erupted. Sabin interrupted his polio research during the war to develop vaccines for other diseases that affected the troops, according to the Sabin Vaccine Institute.

The First Polio Vaccine

• Dr. Jonas Salk, a researcher at the University of Pittsburgh, chose a different approach. Few vaccines were available in the 1940s, and those were manufactured from weakened but live forms of the viruses that caused the diseases, according to the Salk Institute for Biological Studies. Salk believed that only the outer shell of the virus was necessary to confer immunity, not the living microbe. Using a dead virus, Salk developed his inactivated polio vaccine (IPV). IPV was tested and approved for widespread use in 1955, becoming the first available polio vaccine.

Mass Immunizations

• Polio cases dropped from 45,000 in 1957 to 910 in 1962. Sabin had resumed his polio research and in 1961 introduced an oral vaccine made from a live but weakened virus. It was given as drops on a sugar cube or directly on the tongue and greatly simplified administration.

  Sabin's vaccine was preferred over Salk's injected vaccine and was used almost exclusively from its introduction until 1997. By then, polio had been eradicated from the northern hemisphere. The live virus of the oral vaccine thus became a liability. Although rare, it caused poliomyelitis in some people, particularly those with weakened immune systems. The American Committee on Immunization Practices, advisers to the Centers for Disease Control and Prevention, recommended Salk's IPV as the preferred vaccine in 1997.

Current Vaccine Recommendations

• The current polio vaccine recommendations issued by the CDC are for four doses of IPV. Doses are administered to infants at 2 months, 4 months, between 6 and 18 months and as a final booster between 4 and 6 years.