Jonas Salk life and biography

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Jonas Salk biography

Date of birth : 1914-10-28
Date of death : 1995-06-23
Birthplace : East Harlem, New York, United States
Nationality : American
Category : Science and Technology
Last modified : 2010-07-14
Credited as : Health and medical scientist, biologist and microbiologist,

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Jonas Salk , also known as: Jonas E. Salk, Jonas Edward Salk, born October 28, 1914 in East Harlem, New York, United States - died June 23, 1995 in La Jolla, California, United States was an American health/medical scientist, biologist, micobiologist and writer.

American microbiologist Jonas Salk was celebrated worldwide for developing the vaccine that ended the threat of the dreaded polio virus. He discovered that a "killed virus," or a virus made inactive with a formaldehyde solution, is capable of serving as an antigen, or an agent that prompts the body's immune system to produce antibodies that will attack invading organisms. This realization enabled Salk to develop a polio vaccine composed of killed polio viruses, producing the necessary antibodies to help the body ward off the disease without itself inducing polio.

Chooses medical career

The oldest son of Jewish immigrants from Poland, Jonas Edward Salk was born in East Harlem, New York, on October 28, 1914. His father, Daniel B. Salk, was a garment worker, and his mother, Dora Press Salk, encouraged his academic talents. They sent Salk to Townsend Harris High School for the gifted, where he showed he was both highly motivated and high achieving. After graduating at the age of fifteen he enrolled in the legal program at the City College of New York. Ever curious, Salk also attended science courses and quickly decided to switch fields. He earned a bachelor's degree in science in 1933, at the age of nineteen, and went on to the New York University School of Medicine. Initially he scraped by on money his parents had borrowed for him, but after his first year he received scholarships and fellowships. During his senior year, he began working with Thomas Francis Jr., with whom Salk would collaborate on some of the most important work of his career.

The day after Salk was awarded his medical degree in 1939 he married Donna Lindsay, a social worker. They later had three sons: Peter, Darrell, and Jonathan. In 1939, Salk also began a two-year internship at Mount Sinai Hospital in New York. Upon completing his internship Salk accepted a National Research Council fellowship and moved to the University of Michigan in Ann Arbor, where he joined Francis, who had become head of the department of epidemiology the previous year. Working on a project for the U.S. Army, the team strove to develop a flu vaccine. Their goal was a "killed-virus" vaccine, in which the virus is made inactive (killed) by formalin, a formaldehyde-methanol solution. The killed virus would be able to kill the live flu viruses in the body as well as produce antibodies that could fight off future invaders of the same type, thus resulting in immunity to the flu. By 1943, Salk and Francis had developed a killed-virus vaccine that proved effective against both type A and B influenza viruses. Salk and Francis were now in a position to begin clinical trials.

Rejuvenates viral research laboratory

In 1946, Salk was appointed assistant professor of epidemiology at Michigan. Around this time he extended his research to cover not only viruses and the body's reaction to them but also their epidemic effects in populations. The following year he accepted the position of associate research professor at the Virus Research Laboratory at the University of Pittsburgh School of Medicine. When Salk arrived, however, he found the staff had no experience with the kind of basic research he conducted. In order to bring the lab up to par, he solicited financial support from outside benefactors. Soon the Virus Research Laboratory represented the cutting edge of viral research.

Begins work on polio vaccine

In addition to building a respectable laboratory, Salk also devoted a considerable amount of time to writing scientific papers on a number of topics, including the virus that causes poliomyelitis (known simply as polio). His work came to the attention of Daniel Basil O'Connor, the director of the National Foundation for Infantile Paralysis, an organization that had long been involved in the treatment and rehabilitation of polio victims. When the two men met, O'Connor was so impressed with Salk that he pledged nearly the entire budget of the foundation to Salk's vaccine research efforts. Polio, which can be traced back to ancient Egypt, causes permanent paralysis or chronic shortness of breath in those it strikes, often leading to death. Children are especially vulnerable to the virus. The University of Pittsburgh was one of four universities engaged in trying to sort and classify the more than one hundred known varieties of polio virus.

By 1951, Salk was able to assert with certainty that all polio viruses fell into one of three types, each having various strains. Some of the viruses were highly infectious, while others were barely so. Once he had determined the virus types, Salk began to work on a vaccine. His first challenge was to obtain enough of the virus to be able to develop a vaccine in doses large enough to have an impact. This task was particularly difficult since viruses, unlike culture-grown bacteria (bacteria produced in a laboratory), need living cells to grow. A breakthrough came when the team of John F. Enders, Thomas Weller, and Frederick Robbins found that the polio virus could be grown in embryonic tissue. For their discovery Enders, Weller, and Robbins were awarded a Nobel Prize in 1954.

Salk subsequently grew samples of all three varieties of polio virus in cultures of monkey kidney tissue, then killed the virus with formaldehyde. He believed it was essential to use a killed virus rather than a live virus (which is weak, though still live), because the live-virus vaccine would have a much greater chance of accidentally inducing polio in inoculated children. He therefore exposed the viruses to formaldehyde for nearly thirteen days. Although Salk could detect no presence of viruses in the sample after only three days, he wanted to establish a wide safety margin. After an additional ten days of exposure, he reckoned that there was only a one-in-a-trillion chance of there being a live virus particle in a single dose of his vaccine. Before proceeding to human clinical trials, Salk tested the vaccine on monkeys. The results were successful.

Encounters skepticism

Despite Salk's confidence in his findings, many of his colleagues were skeptical, believing that a killed-virus vaccine could not possibly be effective. His dubious standing was further compounded by the fact that he was relatively new to polio vaccine research. His competitors in the race to develop the vaccine--most notably Albert Sabin, the leading proponent of a live-virus vaccine--had been working for years and were irked by the presence of this upstart with unorthodox ideas.

As the field narrowed the division between the killed-virus and the live-virus camps widened, and what had once been a polite difference of opinion became a serious ideological conflict. Salk and his primary backer, the National Foundation for Infantile Paralysis, had received minimal support. Undeterred, Salk continued his research. To test the strength of his vaccine, in 1952 Salk administered a type I vaccine to children who had already been infected with the polio virus. Afterward he measured their antibody levels. The results clearly indicated that the vaccine produced large amounts of antibodies. Buoyed by this success, Salk extended the clinical trial to include children who had never had polio.

Conducts largest medical experiment in U.S. history

In May 1952, Salk initiated preparations for a massive field trial in which over four hundred thousand children would be vaccinated. The largest medical experiment that had ever been carried out in the United States, the test began in April 1954. It was directed by Francis and sponsored by the National Foundation for Infantile Paralysis. More than one million children between the ages of six and nine took part in the trial, each receiving a button that proclaimed them a "Polio Pioneer." One-third of the children were given doses of the vaccine consisting of three injections--one for each of the types of polio virus--plus a booster shot. A control group of the same number of children was given a placebo (an inert substance), and a third group was given nothing.

At the beginning of 1953, while the trial was still at an early stage, Salk's encouraging results were made public in the Journal of the American Medical Association. Predictably, media and public interest were intense. Anxious to prevent sensationalized accounts of his work, Salk agreed to comment on the results thus far during a scheduled radio and press appearance. Since this arrangement did not conform to accepted scientific protocol for making such announcements, some of Salk's fellow scientists accused him of being a publicity seeker. Saying he had been motivated only by the highest principles, Salk was deeply hurt.

Becomes a reluctant celebrity

Despite the doomsayers, on April 12, 1955, the vaccine was officially pronounced effective, potent, and safe in almost 90 percent of cases. The meeting at which the announcement was made was attended by five hundred of the world's top scientists and doctors, one hundred fifty journalists, and sixteen television and movie crews. The success of the trial catapulted Salk to instant stardom. He was inundated with offers from Hollywood and with invitations from manufacturers to endorse their products. Salk received a citation from President Dwight D. Eisenhower and addressed the nation from the White House Rose Garden. He was also awarded a congressional medal for great achievement in the field of medicine. Yet when he was nominated for a Nobel Prize, contrary to popular expectation he did not receive the award. Nor was he accepted for membership in the National Academy of Sciences. This slight most likely was a reflection of the discomfort the scientific community still felt about the level of publicity Salk attracted and of the continued disagreement over his methods. Wishing to escape the glare of the limelight, he tried to retreat into his laboratory.

Vaccination campaign temporarily halted

Unfortunately, tragedy served to keep the attention of the world media focused on Salk. Just two weeks after he announced his discovery, eleven of the children who had received the vaccine developed polio. Several more cases soon followed. Altogether, about two hundred children developed paralytic polio, eleven fatally. On May 7 the Surgeon General called the vaccination campaign to a halt. A thorough investigation determined that the defective vaccines were found to have originated from the same source, Cutter Laboratories in California. Cutter had used faulty batches of virus culture that were resistant to formaldehyde. After furious debate and the adoption of standards that would prevent such a reoccurrence, inoculation resumed. By the end of 1955, seven million children had received their shots, and over the course of the next two years more than two hundred million doses of the Salk vaccine were administered, without a single instance of vaccine-induced paralysis. By mid-1961, there had been a 96 percent reduction in the number of cases of polio in the United States compared to the five-year period prior to the vaccination campaign.

After the initial inoculation period ended in 1958, Salk's killed-virus vaccine was replaced by a live-virus vaccine developed by Sabin. Use of the Sabin vaccine was advantageous because it could be administered orally rather than intravenously, and it required fewer "booster" inoculations. However, Salk remains known as the man who defeated polio.

Founds Institute for Biological Studies

In 1954, Salk was appointed professor of preventative medicine at the University of Pittsburgh, then in 1957 he became professor of experimental medicine. The following year he began work on a vaccine to immunize against all viral diseases of the central nervous system. As part of this research Salk performed studies of normal and malignant cells, which pertained to problems encountered in cancer research. In 1960, he founded the Salk Institute for Biological Studies in La Jolla, California. Heavily funded by the National Foundation for Infantile Paralysis (by then known as the March of Dimes), the institute attracted some of the best scientists in the world, all drawn by Salk's promise of full-time, uninterrupted biological research.

When his new institute opened in 1963, Salk became the director and devoted himself to the study of multiple sclerosis and cancer. He made headlines again in 1967 when he married Frances Gilot, the first wife of the Spanish artist Pablo Picasso. During the 1970s, Salk turned to writing, producing books about the philosophy of science and its social role. In 1977, he received the Presidential Medal of Freedom. In the early 1990s, many people looked to him as the scientist would might finally develop a vaccine against the human immunodeficiency (HIV) virus. Although Salk continued to strive for scientific breakthroughs, he chose not to move into this field of research. Salk died of heart failure in La Jolla, California, on June 23, 1995.

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