Science Magazine Examines Feasibility of HIV Vaccine
Science magazine in its July 1 issue examined 125 questions "that scientists themselves are asking" on a broad range of issues, including whether an HIV vaccine is feasible. Skeptics believe that an HIV vaccine is not possible because the virus reproduces rapidly and with many errors, meaning that no vaccine could fight all strains of HIV. In addition, researchers have had no success developing vaccines against pathogens that adapt to overcome the immune system, such as HIV, the parasite that causes malaria, the hepatitis C virus and the tuberculosis bacillus. However, vaccine developers "have solid reasons to believe they can succeed," according to Science. Researchers have developed vaccines that protect animals from simian immunodeficiency virus, an HIV-like virus that infects chimpanzees. In addition, some people do not contract HIV despite repeated exposure to the virus, suggesting that something is able to prevent infection. Furthermore, a small number of HIV-positive people never become sick with AIDS-related illnesses, and others can be infected for at least 10 years before their immune systems show any signs of weakening. Scientists also have discovered rare antibodies that can kill the virus in test tube experiments, according to Science. Researchers initially focused on vaccines designed to stimulate production of antibodies against HIV's surface protein, but those vaccines were unsuccessful in animal and test tubes studies and large-scale clinical trials, Science reports. Researchers now are looking closely at other approaches, including stimulating cellular immunity, the body's second line of defense. Researchers also are examining genetic variability among people who seem to be most susceptible and most resistant to HIV infection and other diseases. "Wherever the answer lies, the insights could help in the development of vaccines against other diseases that, like HIV, don't easily succumb to immune attack and that kill millions of people," Science reports (Cohen, Science, 7/1).
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