HIV Digest	HIV Digest Archive

Two new vaccines designed to prevent an HIV-like virus that strikes monkeys have shown promising results in preliminary studies in primates.

Dr. Raul Andino of the University of California-San Francisco presented a study demonstrating the first time that a vaccine has protected a primate from infection with highly virulent simian immunodeficiency virus (SIV) introduced to the body through the vagina. The researchers made the vaccine from several strains of poliovirus that had been modified to contain gene fragments from SIV. The researchers injected seven macaques with two cocktails of 20 strains of the transgenic polioviruses. Twelve animals did not receive the vaccine. When SIV was administered to the macaques vaginally, four of the seven vaccinated animals exhibited "substantial protection." In addition, two of the vaccinated animals appeared to be completely protected, indicating no evidence of infection. After 48 weeks, all seven animals remained healthy. In contrast, all 12 controls became infected and six developed clinical AIDS 48 weeks after being tested.

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In another study testing DNA/poxvirus vaccine, led by Dr. Harriet L. Robinson of Emory University in Atlanta, Rhesus macaques were immunized with a series of high- or low-dose vaccinations. Seven months later they were given SIV rectally. Although SIV infected all of the vaccinated and control monkeys, the 20 animals receiving a high dose of the vaccine achieved the best control. For more than eight months, the researchers have been unable to detect­or just barely detect­SIV RNA in 19 of the 20 animals that received the high-dose vaccination; this suggests relatively inactive infection. "The National Institutes of Health will be testing an HIV version of our vaccine in humans," Robinson said. "Initial safety trials will begin in early 2002," she said.

Editor's Note: from Reuters Health