Salk , Jonas Edward
(1914–1995) American microbiologist
Salk was born in New York City, the son of a garment worker. He was educated at the City College of New York and at New York University Medical School, where he obtained his MD in 1939. In 1942 he went to the University of Michigan where he worked as a research fellow on influenza vaccine under Thomas Francis. In 1947 he moved to the University of Pittsburgh, serving as professor of bacteriology from 1949 onward. Here Salk began the work that eventually led to the discovery of a successful polio vaccine in 1954. After this breakthrough Salk was invited in 1963 to become director of the Institute for Biological Studies at San Diego, California, known more simply as the Salk Institute – soon to emerge as one of the great research centers of the world.
Salk was not the first to develop a vaccine against polio for in 1935 killed and attenuated vaccines were tested on over 10,000 children. It turned out, however, that not only were the vaccines ineffective, but they were also unsafe and probably responsible for some deaths and a few cases of paralysis.
By the time Salk began his work in the early 1950s a number of crucial advances had been made since the 1935 tragedy. In 1949 John Enders and his colleagues had shown how to culture the polio virus in embryonic tissue. Another essential step was the demonstration, in 1949, that there were in fact three types of polio virus with the inconvenient consequence that vaccine effective against any one type was likely to be powerless against the other two.
Salk had to develop a vaccine that was safe but potent. To ensure its safety he used virus exposed to formaldehyde for up to 13 days and afterward tested for virulence in monkey brains. This, in theory, allowed a large safety margin, for Salk could detect no live virus after only three days.
To test its potency Salk injected children who had already had polio and noted any increase in their antibody level. When it became clear that high antibody levels were produced by the killed vaccine Salk moved on to submitting it to the vital test of a mass trial. Two objections were raised to this. One from Albert Sabin that killed vaccine was simply the wrong type to be used and a second, from various workers, who claimed to find live virus in the supposedly killed vaccine.
Despite such qualms Salk continued with the trial administering in 1954 either a placebo or killed vaccine to 1,829,916 children. The evaluation of the trial was put into the hands of Francis, who, in March 1955, reported that the vaccination was 80–90% effective. The vaccine was released for general use in the United States in April 1955.
Salk became a national hero overnight and plans went ahead to vaccinate 9 million children. However within weeks there were reports from California in which children developed paralytic polio shortly after being vaccinated. After a period of considerable confusion it became clear that all such cases involved vaccine prepared in a single laboratory.
After several days of almost continuous debate, the decision was taken to proceed and, by the end of 1955, 7 million doses had been administered. Further technical improvements were made in the production process. These safeguards would either eliminate any further cases of live vaccine or if a live virus did manage to penetrate all defenses it should make its presence known long before its use in a vaccine.
The courage shown by Salk in persisting with his vaccine was clearly justified by the results for the period 1956–58 – 200 million injections without a single case of vaccine-produced paralysis.

Scientists. . 2011.

Look at other dictionaries:

  • Salk, Jonas Edward — Médico y microbiólogo estadounidense, nacido en Nueva York en 1914. Consiguió, en 1953, cultivar los tres tipos de virus de la poliomielitis más comunes, inactivarlos con formaldehido y lograr la primera vacuna contra la poliomielitis. Medical… …   Diccionario médico

  • Salk,Jonas Edward — Salk (sôlk), Jonas Edward. 1914 1995. American microbiologist who developed the first effective killed virus vaccine against polio (1954). * * * …   Universalium

  • Salk, Jonas Edward — ▪ American physician and medical researcher born Oct. 28, 1914, New York, New York, U.S. died June 23, 1995, La Jolla, California   American physician and medical researcher who developed the first safe and effective vaccine for polio.       Salk …   Universalium

  • Salk, Jonas (Edward) — born Oct. 28, 1914, New York, N.Y., U.S. died June 23, 1995, La Jolla, Calif. U.S. physician and researcher. He received his M.D. from New York University. Working with other scientists to classify poliovirus, he confirmed earlier studies that… …   Universalium

  • Salk, Jonas (Edward) — (28 oct. 1914, Nueva York, N.Y., EE.UU.–23 jun. 1995, La Jolla, Cal.). Médico e investigador estadounidense. Se graduó de médico en la Universidad de Nueva York. Trabajando con otros científicos en la clasificación del poliovirus, confirmó los… …   Enciclopedia Universal

  • Salk, Jonas Edward — (b. 1914)    Discoverer of anti polio vaccine. As a New York research professor at the University of Pittsburgh, Salk evolved the anti polio vaccine which bears his name and which is now in worldwide use. From 1961 to 1963, he was an adviser on… …   Who’s Who in Jewish History after the period of the Old Testament

  • Jonas Edward Salk — Salk, Jonas Edward Médico y microbiólogo estadounidense, nacido en Nueva York en 1914. Consiguió, en 1953, cultivar los tres tipos de virus de la poliomielitis más comunes, inactivarlos con formaldehido y lograr la primera vacuna contra la… …   Diccionario médico

  • Jonas Edward Salk — Jonas Salk Jonas Salk en 1988. Jonas Edward Salk (né le 28 octobre 1914 et décédé le 23 juin 1995), était un biologiste américain et inventeur du premier vaccin contre la poliomyélite …   Wikipédia en Français

  • Jonas Edward Salk — Jonas Salk, 1988 Jonas Edward Salk (* 28. Oktober 1914 in New York City; † 23. Juni 1995 in La Jolla (Kalifornien)) war ein US amerikanischer Arzt und Immunologe. Er entwickelte den inaktivierten Polioimpfstoff gegen Kinderlähmung (Polio). Salk… …   Deutsch Wikipedia

  • Jonas Edward Salk — noun United States virologist who developed the Salk vaccine that is injected against poliomyelitis (born 1914) • Syn: ↑Salk, ↑Jonas Salk • Instance Hypernyms: ↑virologist …   Useful english dictionary

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