PrEP for Women
What Is PrEP?
PrEP stands for Pre-Exposure Prophylaxis. It means taking medicine before being exposed to something to prevent yourself from getting a disease or condition. We use several kinds of medicine this way.
One example is taking anti-malaria medication when we travel to areas where we might be bitten by mosquitoes that carry malaria. When the medicine is in a person's body before getting a mosquito bite, that person is much less likely to get malaria when she or he is bitten.
For women, another example is taking birth control pills (contraceptives). When contraceptives are already in a woman's body when she is exposed to semen during sex, her chances of getting pregnant are greatly reduced.
When we talk about PrEP in connection to HIV and women, we are referring to the idea of HIV-negative women taking HIV drugs to reduce their risk of becoming infected with HIV if they are exposed to it. Some people use the term 'topical PrEP' to describe the use of microbicide gels. However, in this article when we talk about PrEP, we are referring only to 'oral PrEP,' or HIV drugs taken by mouth as prevention.
How Does PrEP Prevent the Spread of HIV?
Here is how PrEP works:
- When cells are infected with HIV, they become little factories that make thousands of new viruses each day
- HIV drugs work by blocking HIV from making copies of itself
- If an HIV-negative woman already has HIV drugs in her bloodstream when she is exposed to HIV during unprotected sex, for example, the medicine might be able to keep the HIV from making enough copies of itself to "take hold" and prevent her from becoming infected
Truvada Approved for Use as PrEP
Based on the findings of studies mentioned below, in July 2012, the US Food and Drug Administration (FDA) approved the daily use of Truvada (emtricitabine plus tenofovir) as PrEP for sexually active adults at risk of HIV infection. Truvada is a drug often used as part of combination drug treatment for HIV. This is the first time the FDA has approved any drugs for the prevention of HIV.
Has PrEP Been Shown to Be Effective?
Three recent clinical trials have shown that taking Truvada as oral PrEP (one pill by mouth daily) can help prevent HIV. These studies were conducted among men who have sex with men (MSM) and transwomen (people who were born male and identify as women) in the US and Latin America, and among heterosexual women and men in several African countries. The effectiveness for PrEP varied from 44 percent to 73 percent additional protection against HIV infection in these three studies (known as the iPrex, TDF2, and Partners studies).
A fourth study, however, called FemPrEP, was stopped early because it did not seem to help in preventing HIV transmission. FemPrEP was testing the effectiveness of oral daily Truvada in Kenyan, Tanzanian, and South African women at high risk for HIV.
Why Are the Research Findings Unclear?
For any drug or other HIV prevention tool to work, it has to be used; and research tells us that it has to be used correctly and consistently. This is true for condoms and is proving true for PrEP as well. In the four studies mentioned above, the key element in PrEP's success was "adherence," which means taking the drug when and how it is prescribed. In the FemPreEP study, there were low levels of adherence; only about 30 percent of the women in the group receiving the drug took it regularly. Additionally, many women in the FemPrEP study did not consider themselves at risk for HIV. The other three studies had much higher rates of adherence. In all studies, people who took Truvada daily as prescribed were significantly less likely to get infected with HIV when exposed during sex.
We do not yet fully understand all of the reasons why people -- especially women -- have low levels of adherence to oral PrEP. This makes it very important to do more research looking at what issues might affect women's interest in or ability to take a drug for HIV prevention. We may know more about how Truvada is effective for women when the results of a study of over 5,000 HIV-negative women in South Africa, Uganda, and Zimbabwe become available in early 2013 (known as the VOICE study).
It is also important for women to know about and take part in the future research that will look at the unanswered questions about Truvada as PrEP. For more information about understanding, finding, and participating in research studies, see The Well Project's Clinical Trials info sheet.
CDC and WHO Guidelines for PrEP Use
The Centers for Disease Control and Prevention (CDC), which had already provided guidelines for PrEP use among men who have sex with men (MSM), released guidelines in August 2012 for Truvada's use as PrEP by heterosexually active adults. Specifically, the CDC recommends that PrEP be available for heterosexual HIV-negative women and men at high risk for sexually-transmitted HIV infection (for example, those with a partner living with HIV (HIV+)).
It further recommends that PrEP be taken daily as prescribed to maximize its effectiveness and that it be used in combination with other HIV prevention strategies (i.e., condoms). PrEP is not intended to be used alone to prevent the spread of HIV, because it is not 100% effective. It is also important that all those being prescribed Truvada as PrEP test negative for HIV before starting the medication and get tested regularly while taking it.
Lastly, the CDC recommends that HIV-negative women who are pregnant or who are trying to become pregnant talk with their health care providers about the risks and benefits of taking Truvada for PrEP. While the information we have to date does not show negative effects among infants exposed to Truvada during pregnancy, this information comes from HIV+ women taking Truvada. There is very little data on HIV-negative women using Truvada during pregnancy.
The World Health Organization (WHO) has also issued guidance for heterosexually active women and men. It recommends that, in countries where HIV is spread in couples in which one partner is living with HIV, both Viread (tenofovir) and Truvada be considered as possible additional prevention choices for the HIV-negative partner.
The Women's Collective Releases Toolkit for Advancing the Sexual and Reproductive Health of Women Living With HIV/AIDS
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