What did the SALK vaccine help prevent?

Answer 1

Dr. Jonas Salk, the inventor of a vaccine that helped control polio, said at an international meeting here today that a vaccine he has developed might eventually help prevent people already infected with the AIDS virus from developing the deadly disease. Dr. Jonas Salk, the inventor of a vaccine that helped control polio, said at an international meeting here today that a vaccine he has developed might eventually help prevent people already infected with the AIDS virus from developing the deadly disease. His comments were based on preliminary experiments in which three chimpanzees developed strong immune responses after injection with the new vaccine. Dr. Salk and other members of his research team said they did ''not want to raise false hopes,'' but they also held out hope that the vaccine might someday be used as a routine immunization in children. Dr. Salk's was one of several reports that gave a somewhat positive outlook to the prospects for developing an AIDS vaccine, even though many leading experts have expressed growing skepticism that a vaccine will be developed any time soon, if ever. Earlier Failures Researchers so far have been unable to identify a component of the AIDS virus that would stimulate a protective immune response in humans and have failed with other potential vaccines in chimpanzee experiments. These failures have raised questions whether an immune response can be raised against the AIDS virus. But Dr. Salk told a news conference it was clear ''the principles of immunology do apply, even to this agent.'' Dr. Dani P. Bolognesi, an AIDS vaccine researcher at Duke University, told the meeting that the results of Dr. Salk's and other vaccine experiments, though preliminary, ''are the beginnings of piercing the armor'' that seemed to make it ''impossible to protect against this class of virus.'' For the last several years, Dr. Salk has been working with researchers to find a way to protect humans infected with the AIDS virus from developing the disease. He has worked with a team headed by Dr. Clarence Gibbs at the National Institutes of Health in experiments on chimpanzees and with a team headed by Dr. Alexandra Levine at the University of Southern California to test the experimental vaccine on people infected with the virus who have developed swollen lymph nodes but not yet full-fledged AIDS. For both the animal and human experiments, Dr. Salk's team has chosen to develop a different type of vaccine than that used by other researchers. While other groups have prepared a vaccine derived from the outer coat of the AIDS virus, Dr. Salk's team has used the virus stripped of its outer coat. The virus used for immunizations is killed by chemicals and irradiation. Mineral oil is added to the killed virus to help stimulate the immune system. He said the technique was similar to those he used in research on polio and influenza viruses in the 1950s. Dr. Salk's AIDS vaccine is not the classic vaccine, which prevents infection by a virus, but rather appears to prevent a virus that has already entered the body from producing disease. Under his theory, the vaccine would stimulate the body to destroy cells infected with the AIDS virus and prevent it from spreading. The substance was injected at three different times over several months into the muscles of three chimpanzees, the second and third doses being intended as boosters. In the experiments reported today, two chimps were infected with the AIDS virus before they were given the experimental vaccine, but the third was not. From 13 to 15 months after receiving the vaccine, Dr. Gibbs's team injected a large dose of the virus into a vein in each of the three chimps, a standard practice in immunization research. Tests of the immune system of the two chimps that had been previously infected showed they had mounted a strong response to the new viral injections. Members of the Salk team said that they were unable to find the AIDS virus in the two chimps afterwards, indicating that the chimps were apparently able to rid themselves of the virus. Although the researchers said the virus could be hiding somewhere, they could not detect it with laboratory cultures or tests. In contrast, the AIDS virus was detected in the chimpanzee that had not been infected with the virus before receiving the experimental immunization, although that chimp did show a strong immune response. The researchers said the amount of virus detected declined over time. The experimental immunization proved safe and caused no adverse reactions, they said. Dr. Salk compared the stage of the development of the AIDS immunization to the beginning of his work to develop a vaccine against polio. Since November, 1987, Dr. Salk's team has tested the safety of the experimental vaccine on by giving 19 human volunteers three to four doses of the vaccine each year. They have not suffered adverse reactions, Dr. Levine, of the University of Southern California, said. However, some results of the studies on the humans differed from those in the chimpanzees. Two chimps were clear of the virus after vaccination, but the humans who received the same vaccine were not. Dr. Bolognesi, the Duke expert, said he did not know why the humans failed to rid themselves of the virus. the end!