Optimism, Concern Mark Close of AIDS Conference : Medicine: Progress is reported in vaccine research. But the disease continues unabated in Third World.
FLORENCE, Italy — The International Conference on AIDS concluded Friday with renewed optimism that an effective AIDS vaccine will be developed by the year 2000 but concern that progress against the epidemic is being jeopardized by political turmoil among AIDS groups and inadequate attention to the staggering impact of the disease on developing nations.
In one of the most impressive vaccine results, an American research team reported that the use of two different experimental AIDS vaccines in combination produced an immune response in humans against the virus that is far higher than that observed in any previous trials using a single AIDS vaccine, according to Dr. Barney S. Graham of the Vanderbilt University Medical Center in Nashville, Tenn.
“This response is in the range that would be expected for an effective vaccine,” Graham said.
He cautioned that the combination, two injections of a vaccine manufactured by Bristol-Myers Squibb and one injection of a vaccine made by MicroGeneSys Inc., had been tested on only about 20 uninfected individuals. These people have never been exposed to the human immunodeficiency virus, the cause of AIDS. The ultimate effectiveness of the approach in protecting against the virus is unknown.
Several other research teams reported progress in identifying the key aspects of human immunity against HIV.
“Considerable progress has been made” in animal tests and human trials, said Dani P. Bolognesi of Duke University in North Carolina in a plenary address on AIDS vaccine research.
“The previous prevailing pessimism has converted to real optimism,” said Jorg W. Eichberg, a vaccine researcher at the Southwest Foundation for Biomedical Research in San Antonio. Eichberg summarized 17 HIV vaccine trials in chimpanzees.
But other speakers warned that HIV transmission continues unabated in many impoverished countries where medical services and AIDS prevention programs are virtually nonexistent.
“The pandemic remains not only volatile, dynamic and unstable, but it is gaining momentum,” said Dr. Jonathan Mann, of the Harvard School of Public Health, who formerly directed the World Health Organization’s AIDS program. “Its major impacts in all countries are yet to come.”
Mann added that “public complacency is rising and public commitment to (fight AIDS) is declining. A new cycle of public blaming has arisen, discrimination is resurgent, and frontiers threaten to close.”
One of the concerns cited by Mann was evident at the meeting’s closing ceremony. Debate erupted over the contentious issue of travel and immigration restrictions for HIV-infected individuals.
Max Essex, the chairman of next year’s AIDS conference, which is scheduled for Boston, said that meeting will be canceled “unless all American travel and immigration restrictions against HIV-infected people are lifted by Aug. 3.”
Later, Essex, of Harvard University, joined more than 1,000 AIDS activists and conference delegates in a peaceful march to the U.S. Consulate in Florence to protest the restrictions. Few other leading AIDS researchers joined the demonstration.
The Bush Administration had planned to lift the travel and immigration restrictions June 1. But after intense pressure from conservatives, the government changed its mind and delayed a final decision until August.
Most AIDS researchers and organizations believe that HIV-related travel restrictions have no scientific justification and should not exist anywhere in the world.
But there is no such consensus about HIV-related immigration restrictions. Many nations have at least some immigration limitations, including Japan, which was selected this week to hold the 1994 international AIDS conference.
Essex’s announcement represented a victory for some American AIDS activists groups, who had threatened to shut down and disrupt the Boston conference unless all current U.S. restrictions on AIDS-infected foreigners are lifted.
But in addition to expressing his “outrage at the discriminatory U.S. policies,” Essex also blasted the activists’ agenda as short-sighted and counterproductive.
“I am grieved that the crass, domestic, American political agenda and the ultimatums I have received from activists have conspired in a bizarre alliance to deny the free exchange of information necessary to fight AIDS,” he said.
Essex added that the activists were inadvertently aiding conservative political forces. “How ironic, to provide the U.S. right-wing bigots with precisely the outcome they desire. . . ,” he said. “Make no mistake, the Bush Administration does not want an AIDS forum (in the United States), especially not during the election year of 1992. . . . I am not hopeful that there will be a Boston conference.”
AIDS activists said the goal was not to cancel the meeting but to exert maximum political leverage to change American travel and immigration policies.
Other conference delegates also questioned the wisdom of attacking the international AIDS meeting, which has emerged as the single most important forum for the exchange of new scientific information on the many aspects of the disease.
“No country is totally free of AIDS-related discrimination,” said Dr. Robert M. Wachter of San Francisco General Hospital, who served as program director of last year’s international AIDS meeting in the bay city. “The activists may be called to task for the negative consequences of canceling the meeting.”
Several delegates cited the new information on AIDS vaccine research from around the world as an example of the value of the international conference.
Even before a vaccine is ready for widespread use, reported progress may lead to therapies to prevent the transmission of HIV from an infected mother to her newborn and treatments to boost the immune system of people who are already infected with the virus, several scientists said.
Vaccines are injections of weakened or dead germs that are designed to protect against infectious diseases. About a dozen experimental AIDS vaccines are being tested in humans and at least another dozen in chimpanzees or monkeys.
Developing an AIDS vaccine has been considered a daunting task. There is great variation among different strains of HIV as well as scientific uncertainty about how best to construct vaccines that protect against sexually transmitted diseases, such as AIDS.
To be useful in developing nations, where the need is greatest, an AIDS vaccine would also need to be inexpensive, easy to administer and widely available.
The tests combining the two different experimental AIDS vaccines are being conducted through a network of trial sites established by the U.S. government.
One vaccine incorporates the gene for a protein on the surface of the AIDS virus into live vaccinia virus, which is used for vaccination against smallpox. The protein is called gp 160. The second vaccine consists of purified gp 160 protein manufactured through genetic engineering techniques.
Researchers reasoned that the combination of the two approaches would trigger a much greater immune response than either approach used alone, according to Vanderbilt’s Graham, who reported the findings.
Of 12 individuals who received a full series of three injections, more than half had a “high . . . antibody response,” Graham said. No adverse reactions were seen.
In other AIDS vaccine developments:
- Researchers from the United States and Japan reported that a special antibody directed against a small area of the protein on the surface of the AIDS virus protected a chimpanzee against HIV infection.
The area, known as the V3 loop, is the focus of many research efforts, because it is believed to play a key role in HIV infection. Scientists hope that antibodies to the V3 loop will protect against infection by diverse AIDS virus strains.
- Another American research team protected a chimpanzee against AIDS infection by injecting the animal with antibodies obtained from HIV-infected individuals. Both of these experiments may lead to tests of approaches to prevent transmission of the virus from an infected mother to her newborn.
- An Austrian researcher reported that another experimental AIDS vaccine, now being tested in humans, had protected a chimpanzee who was injected with HIV 2 1/2 years after the last immunization had been given. Chimpanzees can become infected with HIV but do not develop full-blown AIDS.
Dr. Josef A. Mannhalter of Immuno AG in Vienna said that the chimpanzee was protected from a large intravenous dose of HIV administered 126 weeks after the last booster vaccine shot. He said it was the longest term of immunity against HIV demonstrated in a chimpanzee to date.
