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Jonas Salk
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It was a Harvard Medical School researcher, John Enders and his two colleagues, Frederick Robbins and Thomas Weller who discovered how to grow poliovirus in the laboratory in 1948. Thanks to their pioneering work, today we have almost forgotten about the disease that caused such terror to our grandparents and that has plagued mankind for thousands of years. Enders was a professor of bacteriology and immunology at Harvard Medical School and chief of the research division of infectious diseases at the Children's Hospital Medical Centre. In 1954, together with Robbins and Weller, he won the Nobel Prize in medicine for his groundbreaking achievement. Despite this, it was Jonas Salk and Albert Sabin, whose vaccines were built on Enders' work, who became household names. The medical historian and resident in paediatrics at Harvard-affiliated Children's Hospital, Walt Schalik, said of Salk and Sabin 'they were standing on the shoulders of Enders'. (See article on John Franklin Enders) Jonas Salk was born in New York City on October 28th 1914, the son of Russian-Jewish immigrants. He is known primarily for his work in the development of the first successful vaccine for polio, but he also made significant contributions to our understanding of influenza and various other infectious diseases. Salk was the oldest son of a garment industry worker. His parents had no formal education, but they encouraged their children to study hard, in the hope that they would have successful careers and Jonas helped pay for his education by working after school and by earning academic scholarships. When he was accepted at the City College of New York, Jonas was the first member of his family to go to college. Although originally, he planned to study law, he soon became fascinated by medical science. While he was at Medical School at New York University, he was invited to spend a year researching influenza. The virus that causes flu had only recently been discovered and Salk was keen to learn if the virus could be deprived of its ability to infect, while still giving immunity to the illness. Salk succeeded in this attempt and this was the basis for his later work in relation to polio. 'We were told in one lecture that it was possible to immunise against diphtheria and tetanus by the use of chemically treated toxins, or toxoids. And in the following lecture, we were told that for immunisation against a virus disease, you have to experience the infection, and that you could not induce immunity with the so-called 'killed' or inactivated, chemically treated virus preparation. Well, somehow, that struck me. What struck me was that both statements couldn't be true. And I asked why this was so, and the answer that was given was in a sense, 'Because.' There was no satisfactory answer.' Jonas Salk was still only a student when he began to search for a more acceptable answer to his classroom question, and the answer he eventually found led to one of the most important breakthroughs in the history of medicine.In 1939, after he had completed medical school and his internship, Salk continued his study of influenza, the flu virus. At this point in his career, World War 11 had already begun and the public health experts were concerned that there could be a repetition of the flu epidemic that had killed millions in the aftermath of the First World War. Fortunately, the development of the first commercial flu vaccine in 1942 controlled the spread of flu after the war and the epidemic of 1919 did not reoccur. In 1947, Salk accepted a post at the University of Pittsburgh Medical School as head of the Virus Research Laboratory, working on improving the flu vaccine. Whilst there, he also began studying the poliovirus hoping also to create a vaccine against that disease. He spent the next eight years devoting his time to this work, applying the findings from many other scientists to the problem. From some, he found a way to produce large quantities of the virus; from others a way to kill the virus with formaldehyde so that it remained intact enough to cause a response in humans. In 1952 he inoculated volunteers, including himself, his wife and their three sons, with a polio vaccine made from this killed virus. Everyone who received the test vaccine began producing antibodies to the disease, but no one became ill. The vaccine appeared to be safe and effective. The following year, Salk published his results in the Journal of American Medicine, following which, nation-wide testing was carried out. Since the turn of the century, polio outbreaks had become more frequent and in 1952, some estimates recorded 57,628 cases, making it the worst year on record. People were desperate for a breakthrough against polio and in 1955, Salk's former mentor, Thomas Francis Jr., directed the mass vaccination of schoolchildren. More than one million children aged six to nine were inoculated, some with the vaccine and others with a placebo. The vaccine worked, and Salk was hailed as a miracle worker. He refused to patent the vaccine, as he had no desire to profit from the discovery, merely wished to see the vaccine disseminated as widely as possible. The success of the vaccination programme won Jonas Salk unsought fame. The ‘March of Dimes', hoping to boost publicity and donations to fund more vaccination programmes, acclaimed Salk to the point of offending his colleagues. He had applied the findings of others in a successful bid to prevent the disease, but other researchers and doctors complained that he had found nothing new; he had just applied what was there. However, the timing of his vaccine at the peak of polio's devastation, made the public blind to that. A few years later, Albert Sabin developed a vaccine made from live poliovirus, which could be taken orally, while Salk's vaccine required injection. Salk and Sabin came from two competing schools of vaccine research. Like Louis Pasteur, Sabin believed the way to produce immunity was to create a mild infection with a 'live' but crippled virus and he prepared his competing vaccine accordingly. Salk, on the other hand, knew from the days of his work on the flu virus, that the immune system could be triggered without running the risk of infection using deactivated or 'killed' viruses. There was some evidence that the 'killed' vaccine failed to completely immunise the patient. In the U.S. public health authorities elected to distribute the 'live' oral vaccine instead of Salk's, but tragically, the preparation of the live virus infected some patients with the disease. Since the introduction of the original vaccine, the 'live' vaccine probably caused the few cases of polio reported in the United States. These days, the two vaccines are given in alternating booster shots. Both Salk and Sabin made convincing cases for their respective vaccines, but, as Salk had developed the original one, he was considered to be 'The Man Who Saved the Children' and became a national hero. Needless to say, this caused bad feeling between the two scientists and other researchers who had been working far longer than Salk in an effort to develop a vaccine against polio. 'He shows the world how to eliminate paralytic polio, and you'd think he
had halitosis or had committed a felony'
It should not be forgotten that the vaccines developed by Jonas Salk and Albert Sabin were built on the initial work carried out by Enders, Robbins and Weller. Salk and Sabin became household names, but it was John Enders and his colleagues who won the 1954 Nobel Prize in medicine. In 1963, Salk founded the Jonas Salk Institute for Biological Studies, an innovative centre for medical and scientific research. He continued to conduct research and publish books, some in collaboration with one or more of his sons, who are also medical scientists. His last years were spent searching for a vaccine against AIDS. He died at the age of 80, on June 23rd, 1995 from congestive heart failure. In 1988, the World Health Assembly, the body that overseas the international World Health Organisation, set a goal of eradicating polio worldwide by 2000. Cases have declined dramatically since then, from approximately 31,251 reported cases in 1988 to 6,175 in 1996, with countries reporting no cases of the disease. Acknowledgements John Enders Jonas Salk Polio Eradication |
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