BALTIMORE (AP) â€” An oral AIDS vaccine is under development at the institute headed by Dr. Robert Gallo, co-discoverer of the virus, and is expected to undergo human tests in Uganda in as little as 18 months.
The vaccine could cost $1 or less per dose, providing an inexpensive form of prevention in poor countries hit hardest by AIDS, its backers said Friday.
``I don't feel this announcement is the answer to AIDS, but it's a very important additional step toward the next line of HIV prevention candidates,'' said Gallo, who heads the University of Maryland's Institute of Human Virology.
Francis Omaswa, Uganda's director general of health services who attended the news conference, said a vaccine is the only hope in his country, where millions of people are infected with HIV and can't afford high-priced treatments and drugs.
The vaccine is one of several expected to be tested in Uganda, according to Gallo's institute and the International AIDS Vaccine Initiative.
Seth Berkley, president of the nonprofit initiative, said the vaccine is promising.
Clinical trials of the vaccine, which uses the common Salmonella bacteria, could begin in as little as 18 months, Berkley said. Once in full production, the bacteria used to make the vaccine could be grown in mass quantities, he said.
``This has the potential to be as cheap as any vaccine,'' said Berkley, whose initiative is providing at least $3 million over three years to complete development of the vaccine.
Nearly 70 percent of the world's 33.6 million HIV-infected people live in sub-Saharan Africa. Current efforts to slow the spread of the virus by eliminating risky behavior are not enough because many people do not know they are infected, Omaswa said.
``Even with an 80 percent cut in the prices of drugs, they will still be too expensive for our people'' Omaswa said. ``That brings us back again to a vaccine. It is for this reason, that we have associated ourselves with this initiative.''
The strain of salmonella bacteria responsible for typhoid is genetically altered to be less infectious and to carry portions of the DNA of the HIV virus, which causes AIDS, into the body.
Once the salmonella bacteria invade intestinal cells, the bacteria die, their cells break apart and the HIV DNA they carry is released.
The infected intestinal cells are then hijacked by the HIV and produce a part of the HIV virus, which is not harmful but causes an immune response. Researchers hope that will allow the body to fight off an attack by the real HIV virus.
More than two dozen potential AIDS vaccines have been tried worldwide. Only one, however, has advanced to large-scale testing, the researchers said.
Results of trials of that vaccine, produced by Vaxgen, should be available in late 2002 or early 2003, said Dr. Peggy Johnston, assistant director for AIDS vaccines at the National Institutes of Allergy and Infections Diseases, a part of the National Institutes of Health.
``We see this as a really valuable addition to the field overall,'' Johnston said of the oral vaccine under development by Gallo.