Jonas Salk Biography (1914-1995)
Jonas Salk was one of the United States's best known microbiologists, chieflycelebrated for his discovery of the polio vaccine. His greatest contributionto immunology was the insight that a "killed virus" is capable of serving asan antigen, prompting 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 to ward off the disease without itself inducing polio.
The eldest son of Orthodox Jewish-Polish immigrants, Jonas Edward Salk was born in East Harlem, New York, on 28 October 1914. His father, Daniel B. Salk,was a garment worker, who designed lace collars and cuffs and enjoyed sketching in his spare time. He and his wife, Dora Press, encouraged their son's academic talents, sending him to Townsend Harris High School for the gifted. There, young Salk was both highly motivated and high achieving, graduating at the age of fifteen and proceeding to enroll in the legal faculty of the City College of New York. Ever curious, however, he attended some science courses and quickly decided to switch fields. Salk graduated with a bachelor's degree in science in 1933, at the age of nineteen, and went on to New York University's School of Medicine. Initially he scraped by on money his parents had borrowed for him; after the first year, however, scholarships and fellowships paidhis way. In his senior year, Salk met the man with whom he would collaborateon some of the most important work of his career, Dr. Thomas Francis, Jr.
On 7 June 1939, Salk was awarded his M.D. The next day, he married Donna Lindsay, a Phi Beta Kappa psychology major who was employed as a social worker. The marriage would produce three sons: Peter, Darrell, and Jonathan. After graduation, Salk continued working with Francis, and concurrently 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 to join Dr. Francis, who had been heading up Michigan'sdepartment of epidemiology since the previous year. Working on behalf of theU.S. Army, the team strove to develop a flu vaccine. Their goal was a "killed-virus" vaccine--able to kill the live flu viruses in the body, while simultaneously producing antibodies that could fight off future invaders of the same type, thus producing immunity. By 1943, Salk and Francis had developed a formalin-killed-virus vaccine, effective against both type A and B influenza viruses, and were in a position to begin clinical trials.
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 an invitation to move to the University of Pittsburgh School of Medicine's Virus Research Laboratory as an associate research professor of bacteriology. When Salk arrived at the Pittsburgh laboratory, whathe encountered was not encouraging. The laboratory had no experience with thekind of basic research he was accustomed to, and it took considerable efforton his part to bring the lab up to par. However, Salk was not shy about seeking financial support for the laboratory from outside benefactors, and soon his laboratory represented the cutting edge of viral research.
In addition to building a respectable laboratory, Salk also devoted a considerable amount of his energies to writing scientific papers on a number of topics, including the polio virus. Some of these came to the attention of DanielBasil O'Connor, the director of the National Foundation for Infantile Paralysis--an organization that had long been involved with the treatment and rehabilitation of polio victims. O'Connor eyed Salk as a possible recruit for the polio vaccine research his organization sponsored. When the two finally met, O'Connor was much taken by Salk--so much so, in fact, that he put almost all of the National Foundation's money behind Salk's vaccine research efforts.
Polio myelitis, traceable back to ancient Egypt, causes permanent paralysis in those it strikes, or chronic shortness of breath often leading to death. Children, in particular, are especially vulnerable to the polio 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 oneof three types, each having various strains; some of these were highly infectious, others barely so. Once he had established this, Salk was in a positionto start work on developing a vaccine.
Salk's 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 was particularly difficult since viruses, unlike culture-grown bacteria, need living cells to grow. The breakthrough came when the team of John F. Enders, Thomas Weller, andFrederick Robbins found that the polio virus could be grown in embryonic tissue--a discovery that earned them 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. Salk believed that it was essential to use a killed polio virus (rather than a livevirus) in the vaccine, as the live-virus vaccine would have a much higher chance of accidentally inducing polio in inoculated children. He therefore exposed the viruses to formaldehyde for nearly 13 days. Though after only three days he could detect no virulence in the sample, Salk wanted to establish a wide safety margin; after an additional ten days of exposure to the formaldehyde, he reckoned that there was only a one-in-a-trillion chance of there being alive virus particle in a single dose of his vaccine. Salk tested it on monkeys with positive results before proceeding to human clinical trials.
Despite Salk's confidence, 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; some of his chief competitors in the race to develop the vaccine--most notably Albert Sabin, the chief proponent for a live-virus vaccine--had been at it for years and were somewhat irked by the presence of this upstart with his 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 chief backer, the National Foundation for Infantile Paralysis, were fairly lonely in their corner. But Salkfailed to let his position in the scientific wilderness dissuade him and hecontinued, undeterred, with his research. To test his vaccine's strength, inearly 1952 Salk administered a type I vaccine to children who had already been infected with the polio virus. Afterwards, he measured their antibody levels. His results clearly indicated that the vaccine produced large amounts of antibodies. Buoyed by this success, the clinical trial was then extended to include children who had never had polio.
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 finally got underway in April, 1954, under the direction of Dr. Francis and sponsored by the National Foundation for Infantile Paralysis. More than one millionchildren between the ages of six and nine took part in the trial, each receiving a button that proclaimed them a "Polio Pioneer." A third of the childrenwere given doses of the vaccine consisting of three injections--one for eachof the types of polio virus--plus a booster shot. A control group of the same number of children was given a placebo, and a third group was given nothing.
At the beginning of 1953, while the trial was still at an early stage, Salk'sencouraging results were made public in the Journal of the American Medical Association. Predictably, media and public interest were intense. Anxious to avoid sensationalized versions of his work, Salk agreed to comment onthe results thus far during a scheduled radio and press appearance. However,this appearance did not mesh with accepted scientific protocol for making such announcements, and some of his fellow scientists accused him of being little more than a publicity hound. Salk, who claimed that he had been motivated only by the highest principles, was deeply hurt.
Despite the doomsayers, on 12 April 1955, the vaccine was officially pronounced effective, potent, and safe in almost 90% of cases. The meeting at which the announcement was made was attended by five hundred of the world's top scientists and doctors, 150 journalists, and sixteen television and movie crews.
The success of the trial catapulted Salk to instant stardom. He was inundatedwith offers from Hollywood and with pleas from top manufacturers for him toendorse their products. He received a citation from President Eisenhower andaddressed the nation from the White House Rose Garden. He was awarded a congressional medal for great achievement in the field of medicine and was nominated for a Nobel Prize but, contrary to popular expectation, did not receive it. He was also turned down for membership in the National Academy of Sciences,most likely a reflection of the discomfort the scientific community still felt about the level of publicity he attracted and of continued disagreement with peers over his methods.
Wishing to escape from the glare of the limelight, Salk turned down the countless offers and tried to retreat into his laboratory. Unfortunately, a tragicmishap served to keep the attention of the world's media focused on him. Just two week after the announcement of the vaccine's discovery, eleven of the children who had received it developed polio; more cases soon followed. Altogether, about 200 children developed paralytic polio, eleven fatally. For a while, it appeared that the vaccination campaign would be railroaded. However, it was soon discovered that all of the rogue vaccines had originated from thesame source, Cutter Laboratories in California. On May 7, the vaccination campaign was called to a halt by the Surgeon General. Following a thorough investigation, it was found that Cutter had used faulty batches of virus culture which were resistant to the formaldehyde. After furious debate and the adoption of standards that would prevent such a reoccurrence, the 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 200 million doses of Salk's polio vaccine were administered, without a single instance of vaccine-induced paralysis. By the summer of 1961 there had been a 96 % reduction in the numberof 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 this new vaccine was advantageous because it could be administered orally rather than intravenously, and because it required fewer "booster" inoculations. To this day, though, Salk remains known as the man who defeated polio.
In 1954, Salk took up a new position as professor of preventative medicine atPittsburgh, and 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, studies that had some bearing on the problems encountered in cancer research. In 1960, he founded the Salk Institute for Biological Studies in La Jolla, California; heavily funded by the NationalFoundation for Infantile Paralysis (by then known as the March of Dimes), the institute attracted some of the brightest scientists in the world, all drawn by Salk's promise of full-time, uninterrupted biological research.
When his new institute finally opened in 1963, Salk became its director and devoted himself to the study of multiple sclerosis and cancer. He remained a driven man, thinking nothing of working sixteen to eighteen hours a day, six days a week. In 1968, his marriage ended in divorce, and he made the headlinesagain in 1970 when he remarried, this time to Françoise Gilot, PabloPicasso's first wife and mother of two of the artist's children. During the 1970s Salk turned to writing, producing books about the philosophy of scienceand its social role. In 1977, he received the Presidential Medal of Freedom.
Despite the sense of expectancy that he seemed to encourage, Jonas Salk tookhis successes and failures in stride. In the early 1990s, many people lookedto him as the one would might finally develop a vaccine against the HIV virus. But Salk, though continuing to strive toward scientific breakthroughs, seems content simply to work at his chosen craft. "I don't want to go from one crest to another," he once said, as quoted by Sarah K. Bolton in Famous Menof Science. "To a scientist, fame is neither an end nor even a means to an end. Do you recall what Emerson said?--'The reward of a thing well done isthe opportunity to do more'."
Salk died on 23 June 1995, at a San Diego area hospital. His death, at the age of 80, was caused by heart failure.