The San Francisco Examiner - Wednesday, Aug. 27, 1997
Lisa Krieger, Examiner Medical Writer

But study authors Nancy Padian and Stephen C. Shiboski of UC-San Francisco warn that this low number should not lead women to throw caution to the wind. The risk of infection in any single unprotected sexual encounter can be influenced by many factors, such as how long the partner has been infected, whether he is being treated with anti-viral medicines, and what strain of virus he carries.

"This should not be taken as a measure of risk for an individual, but is very useful for public health planning purposes," said Shiboski, a statistician. "The number is a very rough average that can't possibly represent the many different variables."

In fact, it is known that in other regions of the world where the epidemic now rages, such as Southeast Asia and sub-Saharan Africa, the statistical risk to women is far greater than that found in this Northern California-based study.

The risk of a man's contracting HIV from an infected woman was found to be much smaller -- in fact, too small for the UCSF researchers to calculate accurately. They attribute the disparate risks to biologic differences between the genders. For instance, male ejaculate contains many viral particles. And the large surface area of female vaginal tissue is highly vulnerable to infection.

The study, published in the August issue of the American Journal of Epidemiology, also concluded that four factors -- anal sex, lack of condom use, injection drug use by men and the presence of a sexually transmitted disease (STD) in women -- were risk factors in infection.

"Elimination or modification of these factors would result in reduced transmission of HIV," Padian said.

It is the nation's largest study of heterosexual transmission of HIV. From 1985 to 1995, Padian and Shiboski enrolled 82 HIV-infected women and their male partners and 360 HIV-infected men and their female partners into the study to examine rates and risk factors for heterosexual transmission of HIV.

While no new HIV transmissions occurred during the course of the study, 68 women and two men were infected by their HIV-positive partners before the study began.

HIV-2 lessons?

A study of 1,000 Senegalese female sex workers has discovered an intriguing finding: Women infected with HIV-2 are 70 percent less likely to become infected with HIV-1, a far more virulent virus.

To the Harvard scientists conducting the study, the story has a familiar ring. In the 1790s, physician Edward Jenner determined that milkmaids exposed to a cousin of the deadly smallpox virus -- the weaker, less lethal cowpox virus -- were immune to smallpox. This paved the way for development of a vaccine and eradication of the disease.

The scenario with HIV-1 and HIV-2 is prompting scientists to wonder whether deciphering the mechanisms of HIV-2 might lead to an understanding of how to create immunity against its more deadly cousin.

"We need to find out what specific HIV-2 effect enables this partial protective immunity from HIV-1," concluded Harvard AIDS Institute researcher Dr. Phyllis Kanki in the latest issue of the journal Harvard AIDS Review.

Mother-child transmission

A major international conference on "Global Strategies for the Prevention of HIV Transmission from Mothers to Infants" will take place in Washington, D.C., Sept. 3-6.

The conference seeks ways to control this troubling infection route. While the rate of all new HIV infections is slowing, the rate of mother-to-infant HIV infections is climbing dramatically in developing nations. For information about the conference, call 1-800-749-9620.

Events

"An Introduction to HIV Treatment Options," sponsored by Project Inform, will be offered Sept. 3 from 6:30 to 8 p.m. at the Project Inform office at 1965 Market St., Suite 220. Call (415) 558-8669.

A free one-day meditation class for volunteer and professional caregivers of people with HIV is offered by Hospice by the Bay on Sept. 6 from 10 a.m. to 4 p.m. at the Headlands Institute near Rodeo Beach in the Marin Headlands. Call (415) 626-5900.

"From the Bench to the Bedside: A Look at Molecular Approaches to HIV Therapy," a lecture by Drs. Steven Deeks, John Stansell and Mark Goldsmith, will be held Sept. 11 from 8 to 11 a.m. at S.F. General Hospital, Carr Auditorium. Call (415) 476-4082, ext. 126.

Coopers and Lybrand, the international accounting and consulting firm, is hosting the first annual "Swing for a Cure" golf tournament on Sept. 12 to raise money to upgrade and expand the UCSF AIDS outpatient facility, Ward 86.

Mayor Brown is the honorary chairman of the tournament. Participants include the S.F. Giants, Golden State Warriors, and San Jose Sharks. Coopers and Lybrand is working with the staff of the Giants' "Until There's A Cure Day" to distribute funds from the event. Golf foursomes for the event cost $800; individuals, $225. Call (415) 696-6360.

The toll

John R. Steinhebel, a medical corpsman in the Air Force, founder of a nationally acclaimed dog grooming school, assistant to Dr. Matilde Krim of the American Foundation for AIDS Resarch, and partner of the late New York University Professor Dr. Kenneth Meeks . . . Raymond E. Lokken, 49, a gifted horticulturalist who loved the mountains of Colorado, the waters of Maui and the fresh air of Marin County . . . Irving Cooperberg, 65, who founded Greenwich Village's Lesbian and Gay Community Services Center and headed Congregation Beth Simchat Torah, one of the world's largest gay synagogues, in New York City.

Date Cases Deaths reported

S.F. 7/1 24,509 16,838

Calif. 7/1 101,898 65,257

U.S. 7/1 581,429 362,004

WHO 7/1 8.4 mil 6.4 mil

Figures are cumulative since June 1981.

Note: AIDS statistics can no longer be updated weekly due to a decision by city, state and federal epidemiologists to release new data only four times a year.

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