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Vaginal gel shows effectiveness in preventing HIV in women

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hiv cell that might be blocked in half of women using a vaginal microbicide gelA vaginal microbicide can cut HIV infection rates by 39 percent in women, researchers announced Monday. And female study participants who inserted the gel as directed reduced their chances of contracting HIV by more than half (54 percent). The news is a stunning, positive development— especially for women at risk for sexual transmission—in a field that has been plagued by two decades of failed and aborted trials.

A reliable HIV-prevention method for women has thus far proved hard to come by, leaving many millions of at-risk women subject to their partner’s decision about condoms.

But a gel that can be applied discretely could severely cut back on HIV, a disease that currently infects an estimated 33 million people worldwide. Researchers involved in the new study calculated that if about a third of women in South Africa could use this gel, in the next 20 years, 1.3 million HIV infections—and 820,000 HIV-related deaths—could be prevented in that country alone.

The gel was made with 1 percent of the antiretroviral medication tenofovir (a drug also sold in tablet form as Viread or in the combination treatment Truvada), which stops HIV from replicating inside a person’s cells. It is the first of half a dozen candidates to show robust prevention. It was tested, starting in 2007, in a double-blind, randomized controlled trial of 889 sexually active women ages 18 to 40, in the KwaZulu-Natal province, which is "at the epicenter of South Africa’s ‘explosive’ HIV epidemic," wrote the study’s researchers, led by wife and husband team Quarraisha Abdool Karim and Salim Abdool Karim, of Center for the AIDS Program of Research in South Africa (CAPRISA) and the Department of Epidemiology at Columbia University’s Mailman School of Public Health in New York, respectively.

"Current HIV prevention behavioral messages on abstinence, faithfulness and condom promotion have had limited impact on HIV incidence rates in women, especially in sub-Saharan Africa," the researchers wrote. "This antiretroviral microbicide could potentially fill an important HIV prevention gap, especially for women unable to successful negotiate mutual monogamy or condom use." The gel was recommended to be used up to 12 hours before an anticipated sexual encounter and again up to 12 hours afterward (but with no more than two doses in one 24-hour period). The results of the trial are slated to be presented July 20 at the International AIDS conference in Vienna and were published early online July 19 in Science.

"This is a historic day for HIV prevention research," Mitchell Warren, AIDS Vaccine Advocacy Coalition executive director, said in a prepared statement. The findings are "the first clinical evidence that a microbicide gel can help to prevent the sexual transmission of HIV infection" and are "a great boost to the microbicide field," he noted.

But this use of tenofovir has yet to be approved by any regulatory bodies and thus, it cannot be sold or marketed. And Salim Abdool Karim explained, in a July 19 teleconference, that the work is only "a proof of concept study" and that further research need to be completed to see if the finding can be replicated—and perhaps why more women who used the active gel were not protected. He estimates that it will be at least a year or two before any similar product will be available on the market.

Previous tests of microbicides have failed to generate substantial protection, and in one trial even raised the rate of transmission. "It’s very easy to get depressed," Polly Harrison, founder of the Alliance for Microbicide Development, told in 2008 in discussing previous gel trial failures.

The researchers attribute part of the gel’s success to the fact that it works differently than some previously tested vaginal microbicides that depended on a full vaginal surface covering to protect against transmission. "Tenofovir is not surface-active," Salim Abdool Karim explained at the press briefing. "It goes into the target cells, so it acts at a different point" in the infection process.

As an antiretroviral, tenofovir also cuts the rate of herpes simplex virus 2 transmission, a virus that effectively doubles a woman’s chances of getting HIV, Salim Abdool Karim noted. Although the study was not designed to study this aspect of tenofovir, "it would reduce the presence of HSV-2 in the long term," thereby likely also helping to reduce HIV rates, he said.

Although the transmission rate was much improved over previous vaginal microbicide gel studies, 39 percent is hardly a perfect solution—it is not wildly higher than the researchers’ pre-study goal of a 33 percent efficacy cut off. Nevertheless, the success rate might pack some surprises for the microbicide community. "I think most people here are skeptical that it’s going to work," Salim Abdool Karim said from the International AIDS conference in Vienna.

The gel’s effectiveness also seemed to taper off over the 30-month study period. Rather than an issue with the medication, the researchers speculate that it was "largely due to diminishing adherence," Salim Abdool Karim said, noting that women might have come to internalize the disclaimers repeated at their monthly clinic visits—that the gel was only experimental and might not work at all.

If the gel does get approval from South African regulatory bodies, it might make it into clinics cheaply, as the Contraceptive Research and Development program and tenofovir maker Gilead Sciences agreed that the South African government could make the product without paying royalties. The new results join other encouraging preventive findings, including the November 2009 news that an HIV vaccine trial in Thailand had met with a 26 to 31 percent effectiveness rate. Other trials testing different dosing of tenofoir and other antiretroviral microbicide gels for HIV prevention in women are ongoing.

Image courtesy of iStockphoto/Eraxion

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  1. 1. SpaceGoat1701 6:20 pm 07/19/2010

    "A reliable HIV-prevention method for women has thus far proved hard to come by, leaving many millions of at-risk women subject to their partner’s decision about condoms."

    The author seems to imply the decision is the man’s alone. What misogynist swill!

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  2. 2. Sael Palani 8:55 pm 07/19/2010

    Agreed Spacegoat1701! All this money spent on researching a gel that makes sexual safety women’s responsibility (once again) to ensure they don’t DIE because some guy doesn’t want to wear a bloody condom. I have a solution aside from massive public education campaigns: Any guy who doesn’t want to wear a condom doesn’t get to have sex. How ’bout that?

    And you know the porn industry is going to lurve this. It’s going to be a nice sense of false security. All the piddly attempts at regulating condom usage in porn industry are going to mean nothing if this gel is marketed in North America.

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  3. 3. keithdouglas322 10:22 pm 07/19/2010

    So much for women using their voice to maintain sovreignty over their own bodies. If a guy doesn’t want to use a condom she has, and has always had, the right to kick him to the curb. It is each individual’s responsibility to make decisions about what another may do with his or her body. Mutual responsibility for avoiding pregnancy is not the same as individual responsibility for avoiding disease. Apples and oranges. If a woman decides to have sexual relations with or without a condom, it is on her. That is unless he chooses to use one against her wishes.

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  4. 4. Gojira1974 4:04 am 07/20/2010

    You morons do realize that this is South Africa where they really DON’T always have a choice.

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  5. 5. krabcat 3:21 pm 07/20/2010

    um…your responses might be correct if we were talking about a country where women have such rights. Although South Africa has been getting better in the past decade or so, they are still not as good as you seem to think they are.

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  6. 6. jgrosay 11:02 am 07/21/2010

    It was known from more than 20 years, that some contraceptive gels and vaginal tablets did counteract HIV transmission for the women that used them, but the issue is no means, even condoms, can guarantee 100% full protection against HIV or other sexually transmitted diseses. I don’t want to say this, but there is no safe sex, as there is no pregnancy-absent sex ( I mean in heterosexual relations), all ways have some failure rate. The sole 100% preventive medicine is no sex at all, although married sex can be considered safer, and for sure is the only morally acceptable kind of it.

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  7. 7. ld 12:39 am 07/23/2010

    They have invented FEMALE condoms now and the man does not even know the woman is wearing it. It would be great if more people knew that this exists. please pass it on. safe sex

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  8. 8. ld 12:41 am 07/23/2010

    They have invented FEMALE CONDOMS now at and the man will not even notice the condom is in .

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  9. 9. Patsy 4:13 pm 07/26/2010

    Any product that prevents HIV transmission in men, women, homosexual people and transmission between mother and child is deservidly welcome. I feel uncomfortable about this type of research however – it’s the latest in a series of studies that is almost entirely done in developing countries and in which HIV-negative women are exposed to HIV positive men. Half of the 900 women did not get the active gel but got instead an inert gel, although it is reported the women were given condoms and provided with counselling. Given the resistence of men to using condoms, this does not seem a realistic alternative. Not surprisingly, more of the women using the inert gel converted to HIV positive. The active gel provided between a 39% to 52% chance of not contacting HIV. What of the active gel women outside this group? And how many of the women using the inert gel became HIV positive? Why did this study have to last 30 months? I’m thinking ethics.

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