Scientists Debate HIV Prevention Products

In Kampala, Uganda, a laboratory technician collects blood for an HIV test. i i

A laboratory technician collects blood for an HIV test from a patient at the Infectious Diseases Institute (IDI) in Kampala, Uganda. Marco Di Lauro/Getty Images hide caption

itoggle caption Marco Di Lauro/Getty Images
In Kampala, Uganda, a laboratory technician collects blood for an HIV test.

A laboratory technician collects blood for an HIV test from a patient at the Infectious Diseases Institute (IDI) in Kampala, Uganda.

Marco Di Lauro/Getty Images

For years now, scientists have tried to find a product that would give women in developing countries more control in protecting themselves against sexually transmitted HIV. They have yet to find a universally effective and safe method.

A recent study presented at the Conference on Retroviruses and Opportunistic Infections in Montreal highlighted the dilemmas in this field — a gel to prevent HIV worked in 30 percent of the women who tried it. Many scientists have dismissed those results because there was a 1-in-10 chance that the effect was due to chance. Others who had great expectations riding on the findings were encouraged.

Still, Tachi Yamada, director of global health policy for the Bill and Melinda Gates Foundation, was concerned that the results were presented as promising.

"To me, it was very unfortunate," says Yamada. "In fact, there should be a little bit of concern that this is now the fifth or sixth trial that came out statistically insignificant."

Scientists say the negative results could have been predicted. In at least two previous clinical studies, the women who were given the vaginal gels containing spermicides faced an increased likelihood of becoming infected with HIV. The PRO 2000 used in this study contained compounds similar to those used in other studies that provided no protective effect.

To understand why so much effort is invested in finding a product that women in developing countries can use independently, researcher Sharon Hillier at the University of Pittsburgh School of Medicine says you have to put yourself in the mind of a 19-year-old Zambian woman who just got married.

She needs to have children because her value as a woman is very much associated with her ability to have a baby, and she needs to breast-feed, Hillier explains. She also needs to have sex with her husband, but if she asks him to use condoms, he will think she has been unfaithful or that she doesn't trust him. He might even beat her up, Hillier says.

As a result, that young Zambian woman needs something that she can use, possibly without her husband knowing it, that will allow her to stay uninfected.

Lorie Heise of the Global Campaign for Microbicides acknowledges that the results were statistically insignificant, but she wasn't entirely disappointed. She has even greater hopes in the next generation of microbicide, which will contain lower doses of anti-AIDS drugs to block the virus.

Perhaps the most promising aspect of this study, Heise says, is that more than 80 percent of the women reported that they used the gel consistently, even knowing that they may have simply gotten a placebo that did not contain PRO 2000. And most of the women stayed with the study for two years — to Heise a sure sign that women in developing countries will use a microbicide if one is found to be effective against HIV. After all, she adds, gels are sexier than condoms.

"We spend enormous sums in the United States to buy sexual lubricants to make sex more fun," Heise says. "It's a selling point we shouldn't underestimate ... Even in parts of the world like Africa where that practice hasn't been as common, people are liking the gels."

She notes that the gel appeared to be more effective among the highest level of users — those who used it almost every time. These findings were based largely on self-reports, and not everyone is convinced that similar participation could be achieved under real-world conditions, where the women are not counseled once a month as they were in this study. Yamada, for one, is not quite convinced a microbicide could be found that would work reliably enough that women would use it.

Yamada imagines a woman trying to maintain confidentiality about her sexual life with her husband. He thinks that using microbicides in small villages and towns in Africa would make it difficult to maintain privacy.

"[The microbicides] come in a paper packet, and there's a plastic applicator, and you have to apply the plastic applicator presumably around the sex act," Yamada says. And then you have to dispose of the packet.

"So what happens if it gets put out around your hut, and then everybody in the village knows you had sex and that you suspect your husband has HIV," Yamada explains.

He has higher hopes for another prevention method — the pre-exposure pill, or PrEP — that involves an uninfected person using an anti-AIDS drug. Some of the compounds being studied are longer-acting, so they could be taken once a day or once a month to block infection. Heise says the pills would create a separate set of challenges for a woman in Africa. If it turns out that someone else, such as her husband, were infected with HIV, the wife might be forced to share the medicines.

Only people who don't face the same risk as women in developing countries would quibble over what prevention method was used, says Hillier of the University of Pittsburgh. "Almost all the women I've talked to in this [study], told me their aunts had died, their brothers had died of HIV."

Hillier says the women were emphatic, "They didn't care if it was a pill or a gel or a diaphragm, they wanted something to help protect them from HIV."

Scientists like microbiologist John Moore at Weill Cornell Medical College is concerned about both gels and pills since they are now adding to them the same drugs that are used to treat HIV. He says that we should proceed more cautiously because of the risk of undermining the effectiveness of the drugs.

"The use of antiretrovirals for prevention could create the spread of resistant variants that compromise treatment programs."

This happened with nevirapine, which has proven effective in preventing the transmission of HIV from mother to child. The problem is that nevirapine, a relatively inexpensive drug used in drug combination treatments widely used in developing countries, can't be used by mothers who developed resistance when they took it to protect their newborns against HIV. That would leave poor women with fewer treatment options.

There needs to be one coordinating body to establish guidelines for this kind of research, according to Moore. As it is, he says, too many different researchers and organizations are chasing concepts that are too similar, making the same mistakes that were made in HIV vaccine research.

"Before hurrying off in a certain direction," Moore says, "you need to know that you're heading off in the right direction, and there are times when the vaccine and the microbicide fields ... have almost acted like they're racing to be the first lemmings off the cliff."

In response to these criticisms, Hillier and other members of the Alliance for Microbicide Development say they are working to create greater coordination and to pursue the best scientific leads. What they cannot do is wait, they say, because the need is too great.

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