Microbicides

What Are Microbicides?

Microbicides are gels, films, or suppositories that can kill or neutralize viruses and bacteria. Researchers are studying both vaginal and rectal microbicides to see if they can prevent sexual transmission of HIV. A safe, effective, and affordable microbicide against HIV could help to prevent many new infections.

For more information on microbicides, see NIAID’s HIV/AIDS: Topical Microbicides.

Can Microbicides Prevent HIV Infection?

The answer to this question now appears to be “Yes”—though more studies are needed to be sure.

In July, 2010, researchers attending the 2010 International AIDS Conference in Vienna, Austria announced exciting news about the CAPRISA 004 Microbicide Study . In that study, researchers put an antiretroviral drug into a vaginal microbicide gel and told the women participating in the trial to use the gel before and after sex to protect against HIV transmission.

The study results found that, overall, the gel was 39% effective in reducing the women’s risk of becoming infected with HIV during sex. The more frequently the women used the gel as intended, the more effective it was in protecting them from HIV infection.

The gel was also 51% effective in preventing genital herpes infections. Since having a sexually transmitted infection like herpes increases your risk of contracting HIV, this is another important result.

If other studies of microbicide gels confirm these results and the microbicides are approved for licensure by the appropriate regulatory agency and made available, microbicides could prevent millions of new HIV infections over the next decade.

To learn more about the microbicide trials, read the CAPRISA 004 Study Details or the Microbicide Trials Network’s Understanding the Results of CAPRISA 004 . You can also watch the Kaiser Family Foundation’s webcast of the announcement in Vienna .

Why Are Microbicides So Important?

HIV is spread predominantly through sexual transmission. Right now, the best HIV prevention options for sexually active people are being mutually monogamous with an HIV-negative partner and using condoms consistently and correctly. For many people, however, these options are not possible.

It is believed that topical microbicides might be more effective than condoms in preventing HIV infection because they would be easier to use and women would not have to negotiate their use, as they often must do with condoms. Worldwide half of the people living with HIV are women. So, public health professionals are particularly interested in developing microbicides for women who aren’t able to get their male sex partners to use condoms. Microbicides would make it possible for a woman to protect herself and her partner from HIV without his cooperation or knowledge—a particularly important factor for commercial sex workers (prostitutes) or women in abusive relationships.

Microbicides might also make it possible someday for women to protect themselves from HIV while still allowing them to get pregnant if they wish.

For more information, see the Microbicide Trials Network’s Microbicides: A Promising Strategy .

See also UNAIDS' (the Joint United Nations Programme on HIV/AIDS) 2008 series: Microbicides: why are they significant? (Part 1) and Microbicides: challenges to development and distribution (Part 2) .

Can I Use A Microbicide to Protect Myself from HIV Infection?

Not yet. The CAPRISA study results are exciting—but even if those results are duplicated in other clinical trials, it will probably be several years before microbicides are available to the public. Researchers will have to be sure that the product is both effective in preventing HIV infection and safe for people to use.

For now, the best forms of protection against sexual transmission of HIV continue to be:

• Being mutually monogamous with an HIV-negative partner
• HIV testing—so that you know your own HIV status and your partner’s too
• Using condoms consistently and correctly

Where Can I Learn More About Microbicide Research?

In addition to the sources linked above, see the Global Campaign for Microbicides or the International Partnership for Microbicides .