New evidence presented here at an international scientific conference on AIDS suggests a more ominous future for the disease in the United States than most official pronouncements have indicated.
A study of New York homosexual males, for example, suggests that a higher proportion of those infected with the AIDS virus are likely eventually to develop the fatal illness than is usually stated.
The study found that about one-third of those exposed to the virus as of 1982 have contracted AIDS. As time goes by, even more of the 80 persons in the original study group are expected to become ill.
The federal Centers for Disease Control has said that about 5 to 10 percent of those whose blood tests positively for exposure to the virus eventually will get the disease. However, Dr. Harold Jaffe of the CDC, in a telephone interview from Atlanta, said those estimates are about to be revised upward, a move which would lend further support to the findings of the New York study.
Jaffe said that researchers have monitored different groups of exposed people, and hoped that after an initial burst of people contracting AIDS, few of the rest of the exposed group would get the disease.
"Unfortunately, more than six years after the start of follow-up, those exposed are still coming down with AIDS," Jaffe said. "It is distressing that in the studies so far, we are not seeing a decrease in illness . . . there is a continued high risk."
An additional 25 percent of exposed people, in CDC estimates, come down with the AIDS-related complex, a less severe immune system disease that appears often to lead to AIDS itself. The CDC is expected to increase this number as well in an update expected within some weeks.
Over 16,000 people in America have AIDS. About 1.75 million Americans are estimated to be infected, and this number has been growing by more than 1,000 per day.
Scientists suggested last fall that the proportion of infected persons actually getting the disease might rise beyond original estimates. The new study and the CDC's planned revision of the figures seem to bear out those suggestions.
Dr. William Blattner, of the National Cancer Institute, who reported the findings, said they may provide "a window to the future of AIDS," but he emphasized that only a small group was studied and that its members were highly sexually active, having many sexual partners. Thus they may not represent the majority of currently infected persons who may be less heavily infected.
Blattner said it was probable that the men had become infected several years before 1982 and that they were nearer the end of the virus' long incubation period than are most of those currently infected.
Blattner likened AIDS infection, in which the virus may remain dormant for many years, to a clock ticking away. It may yet turn out that people with light infections will develop heavier infections as the viruses multiply within the body, he said.
Another study, in Haiti, found that although the disease there was once mostly confined to men, it is spreading rapidly to women as a result of heterosexual transmission.
In 1979 only 12 percent of Haitian AIDS patients were women. Today the proportion is up to 30 percent in a total AIDS population of 363 and is expected to climb above 40 percent by 1988.
This finding, along with evidence from Africa where AIDS afflicts men and women about equally, suggests that the disease may well spread among heterosexuals as well as it does among homosexuals.
"This is transmitted both ways," concluded Dr. Jean W. Pape, a Haitian AIDS researcher.
Blattner, commenting on Pape's findings, said it was wrong to regard AIDS as a homosexual disease. "It's a sexual transmitted disease and if we can get that message across to the American public, maybe we can prevent it from spreading even further there."
The reports were presented at a special conference cosponsored by the French government's Association for Cancer Research and the National Cancer Institute. Participating are more than 50 of the world's leading AIDS researchers from 16 countries including several Caribbean and African nations, China and the Soviet Union.