Slower Spread of AIDS in Gays Seen Nationally

The slowing of the AIDS epidemic among gay men is continuing and is now being seen nationally beyond Los Angeles County, San Francisco and New York City, the metropolitan areas hit earliest and hardest by acquired immune deficiency syndrome.

As a result, federal health officials believe that their previous estimates of both the number of individuals infected with the human immunodeficiency virus and the number who will develop AIDS in the early 1990s were about 15% too high.

The U.S. Centers for Disease Control said that between 800,000 and 1.3 million Americans are currently infected with HIV, a substantial decrease from its previous estimate. In addition, the CDC has revised downward its projection of actual AIDS cases for 1990 from 65,000 to between 53,000 and 57,000.

“We are not ready to declare premature victory by any means, but I can’t help but be a little encouraged by this,” said Dr. James W. Curran, the director of the CDC’s HIV/AIDS program.

Curran said the “cautious good news” was tempered by the continued growth of the epidemic in intravenous drug users, heterosexuals and newborns, as well as “very sobering” data on the “severity and inevitability” of life-threatening immune system damage in infected individuals.

“There is no reason for complacency when you have hundreds of thousands of men who are infected and don’t know,” he said in a telephone interview from Atlanta. “ . . . The number of infected people is smaller than we would have predicted, but the prognosis for individuals without therapy is worse than we would have predicted.”

Despite the slowing of the epidemic’s growth rate, new AIDS cases will continue to be diagnosed at high rates, according to health officials. While the number of new cases falls, the number of living AIDS patients is expected to increase markedly as a result of treatment advances.

Public health officials cite several possible causes for the slowdown, including the adoption of safer sexual practices by many gay men to prevent infection and the previous overestimate of the number of infected individuals. The number of full-blown AIDS cases may also be diminished by treatment advances, such as AZT and aerosol pentamidine that can prevent the progression of the disease.

Another possibility is less-complete reporting of AIDS cases now than in the early years of the epidemic, although Curran said “there is not really any evidence of that.” The CDC estimates that between 80% and 90% of all diagnosed AIDS cases are being reported to health officials.

Other health officials are less certain, citing, for example, a June 1989 General Accounting Office report that found substantial undercounting of AIDS cases, perhaps by as much as 33%.

New data on the slowing of the epidemic is contained in publicly available AIDS statistics and in a report on AIDS projections under preparation by the CDC.

Beginning in 1987, there was a leveling off in the number of new AIDS cases among gay men in Los Angeles County, San Francisco and New York City. Together, the three areas account for about a third of the 115,158 AIDS cases that have been reported in the United States.

During 1988 and early 1989, the leveling off of AIDS cases among gay men in these areas continued, according to recent disease statistics that the CDC has adjusted for delays in the reporting of cases.

“There is more evidence of a plateau in these cities than elsewhere,” Curran said. “Whether it is an absolute leveling off or close to a leveling off is unknown.”

A similar but less pronounced trend is now being seen in cases among gay men in other areas of the country, Curran said.

When the 12-month period ending in November, 1989, is compared with the prior 12 months, the overall number of reported AIDS cases declined in the Newark metropolitan area, according to federal AIDS statistics. In addition, reported AIDS cases increased by less than 5% in Washington and by less than 10% in Chicago and Houston, three other metropolitan areas with large caseloads.

Despite the growth of the AIDS epidemic in other risk groups, gay men, including the small minority who are also intravenous drug users, continue to dominate AIDS statistics, accounting for about two-thirds of all cases nationally.

Confusion about the size of the AIDS epidemic sometimes results when public health statistics and news accounts focus exclusively on when cases were reported to health officials, not when the cases were actually diagnosed.

In Los Angeles County, for example, while the number of reported AIDS cases increased by about 12% between 1988 and 1989, the number of cases diagnosed during six-month intervals stayed relatively constant between 1987 and the first half of 1989. This is because some of the cases reported to county officials during 1989 were diagnosed in previous years.

The revised AIDS estimates are based on a CDC workshop held in Atlanta on Oct. 31 and Nov. 1, involving about 70 public health and technical experts. A final report on the meeting is expected to be published within several weeks.

After reviewing new data and the results of refined prediction techniques, CDC officials concluded:

- AIDS cases are likely to increase each year in the United States through 1993, but the actual number of cases each year will be about 15% lower than previously estimated. The new estimate for 1990 is 53,000 to 57,000 cases; the new estimate for 1993 is 67,000 to 90,000 cases. Most of the increase will occur in cases involving intravenous drug use, heterosexual transmission and perinatal infection of children.

- For 1990, the number of AIDS cases in gay men who are not intravenous drug users is estimated at between 29,000 and 31,000. By 1993, it is expected to increase to between 33,000 and 44,000 cases.

- By 1985, about 600,000 Americans had acquired the HIV infection.

- The best current estimate of HIV-infected Americans is approximately 1 million, with a range of 800,000 to 1.3 million infected individuals. By comparison, in 1986, the CDC estimated that between 1 million and 1.5 million Americans were infected with the virus, a figure it now concedes was “too high.”

- The “minimum” estimate of new HIV infections that are occurring each year is about 50,000. Other estimates range as high as 100,000 to 200,000.

- The annual number of new HIV infections in newborns is between 1,500 and 2,000.

Between 17% and 19% of living HIV-infected people are estimated to have fewer than 200 T4 white blood cells per cubic millimeter of blood. Such patients have severely damaged immune systems and are at the highest risk of developing AIDS or dying. An additional 41% to 45% have between 200 and 500 T4 cells. All these patients, according to Curran, should be considered for approved or experimental HIV therapies.

T4 cells are key infection-fighting white blood cells that are destroyed by the AIDS virus. Healthy individuals have at least 800 to 1000 T4 cells per cubic millimeter of blood.

TRENDS IN REPORTED AIDS CASES

The rate of growth of the AIDS epidemic has slowed markedly. These are the numbers of AIDS cases reported nationally and in Los Angeles County, San Francisco and New York City, the three areas hit earliest and hardest by the disease.

Date of Diagnosis National Los Angeles San Francisco New York City Jan-June ’84 2,551 197 224 769 July-Dec ’84 3,361 269 357 943 Jan-June ’85 4,807 415 426 1,215 July-Dec ’85 6,209 503 460 1,405 Jan-June ’86 8,073 668 594 1,790 July-Dec ’86 9,672 773 727 2,083 Jan-June ’87 12,325 952 759 2,316 July-Dec ’87 13,575 933 800 2,341 Jan-June ’88 14,812 955 819 2,719 July-Dec ’88 14,682 943 726 2,484 Jan-June 1989 14,489 967 820 2,063 TOTAL CASES 115,158 8,409 7,686 22,516

Since beginning of epidemic

Notes: 1989 statistics are less complete than those for earlier years. Statistics for New York City do not include 552 pediatric AIDS cases.

SOURCES: National statistics: Centers for Disease Control, cases reported through Nov. 30, 1989. Los Angeles County Department of Health Services, cases reported through Nov. 30, 1989. San Francisco Department of Public Health, cases reported through Dec. 30, 1989. New York City Department of Health, cases reported through Nov. 8, 1989.