Emily Paulsen

July 29, 2011

July 29, 2011 (Washington, DC) — Women account for more than 50% of the worldwide AIDS epidemic, and a disproportionate number of those women are people of color. In the United States, black women make up a growing share of new AIDS cases; the rate for black women is nearly 20 times the rate for white women.

Although these statistics are dire, new research, presented here at the National Medical Association 2011 Annual Convention and Scientific Assembly, offers hope that the tide will turn on HIV transmission.

"This has been an amazing year for HIV research," Gina Brown, MD, told meeting attendees. Dr. Brown coordinates research on microbicides at the Office of AIDS Research, part of the National Institutes of Health in Bethesda, Maryland. She offered a "walk-through of some of the interesting things we've learned about what puts women at risk for HIV, and some of the interventions available."

The biggest news in HIV prevention, reported recently at the 6th International AIDS Society (IAS) Conference on HIV Pathogenesis, Treatment and Prevention, has been the use of antiretroviral therapy (ART) to reduce the risk for transmission, according to Dr. Brown. The HPTN 052 study showed a 96% reduction in transmission in serodiscordant couples in which the HIV-positive partner received early ART. In another study, once-daily tenofovir/emtricitabine (Truvada, Gilead Sciences) resulted in a 44% reduction in HIV transmission in men and transgender women who have sex with men. In that study, those who adhered to their medications at least 90% of the time achieved a 73% reduction in HIV transmission.

Dr. Brown pointed out that the couples in many of these studies were in steady relationships and volunteered to participate in the study. "Does this sound like the patients you see in your practice?" she asked the audience. She also said that costs and adverse effects might affect the practicality of this solution for many patients.

"When can we give up condoms?," she asked, answering that it would not likely be any time soon.

Dr. Brown said a full HIV prevention toolbox is still needed to reduce the risk for transmission. Education, partner reduction, treatment for sexually transmitted infections, condoms, circumcision, 1% tenofovir gel, and ART all offer varying amounts of protection. All interventions offer only harm reduction at this point, she said, not full protection.

In other areas of HIV research, the role of mucosa in the transmission of HIV has been illuminated, Dr. Brown reported. The natural pH of the vagina offers some protection against HIV transmission, but several factors can compromise or enhance that protection. Sexually transmitted infections, which disrupt that mucosa, increase the risk for HIV transmission. Douching or even washing with soap and water can change the pH level and increase the risk for HIV infection, she said. In contrast, animal studies have shown that the presence of natural lactobacilli might be protective. Semen has some qualities that protect, but they might also alter the optimal pH of the vagina.

Dr. Brown said that studies presented at the recent IAS conference showed that ovulation and pregnancy both seem to increase the risk for HIV transmission. Women who are trying to get pregnant, as well as those who are already pregnant, are at increased risk of contracting HIV from their partners.

These discoveries are particularly significant, as one NMA panelist pointed out, because women who are HIV-positive want to become pregnant as much as women who are HIV-negative. Most cannot afford in vitro fertilization to avoid the risk for transmission of HIV during intercourse.

Interestingly, HIV-negative men were also more likely to contract HIV from their HIV-positive partners during pregnancy.

Dr. Brown discussed another study from the IAS conference — one that found a link between hormonal contraception use (oral contraceptive and injectables) and an increased risk for HIV transmission. In that study, the risk for transmission in 3790 HIV-1 discordant couples in Africa was almost twice as high for both men and women when the woman was using injectable contraception. Dr. Brown said this contraception method might thin the vaginal mucosa and increase the risk for HIV transmission from men to women and from women to men.

Mucosa might also play a role in the high risk for HIV transmission through anal sex, Dr. Brown said. "All mucosa is not created equal," she noted. Rectal mucosa is much thinner and, it appears, less protective.

Some women believe anal sex is a safer choice, but it is actually much more dangerous in terms of HIV risk, Dr. Brown explained. She showed a chart of the comparative risk for different types of sex. Receptive anal sex is 100 times as risky as insertive oral sex, and 5 times as risky as receptive vaginal sex, she said.

It is important to get this message out to teenagers, who sometimes engage in anal sex to reduce the risk for pregnancy and to preserve virginity. They are also less likely to use a condom for anal sex, she said.

Dr. Brown and other panelists have disclosed no relevant financial relationships.

National Medical Association (NMA) 2011 Annual Convention and Scientific Assembly. Presented July 27, 2011.

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