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Preexposure Prophylaxis Case Studies for HIV Prevention
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NEJM July 11, 2012
From the Centre for the AIDS Program of Research in South Africa (CAPRISA) and the University of KwaZulu-Natal - both in Durban, South Africa; and Columbia University, New York.
Case Vignettes
The first patient, a 46-year-old sexually active man who has sex with men, presents for routine primary care. He lives in New York City and reports that he is in a long-term, stable, open relationship with a male partner and that he has had multiple recent sexual encounters with acquaintances. A recent HIV test was negative. He has seasonal allergies, for which he occasionally takes antihistamines, and chronic lower back pain, for which he takes nonsteroidal antiinflammatory drugs on a regular basis. Otherwise he takes no medications and has no known allergies to medications. He had syphilis 10 years earlier for which he was successfully treated. His physical examination is notable only for the fact that he is uncircumcised. You review HIV prevention strategies in detail with him, including the potential benefits of circumcision and of the use of condoms. He has been reading information on the Internet, including information about preexposure prophylaxis (PrEP), and asks whether he should be receiving this therapy.
The second patient, an 18-year-old heterosexual woman in South Africa who has recently become sexually active, presents for voluntary HIV testing. She does not know the HIV status of her male partners. She reports no medical problems, is taking no medications, and has no known allergies to medications. She reports that her older sister recently received a diagnosis of HIV infection. Her physical examination is unremarkable. Testing for sexually transmitted infections is performed. A pregnancy test is negative. She would like to initiate birth control and elects to start taking oral contraceptive pills. She returns to the clinic the following week and is informed that all the tests for sexually transmitted infections, including the HIV test, were negative. She thinks that she had received the hepatitis B vaccination series. She is negative for hepatitis B surface antigen. She is given extensive HIV counseling, and the various HIV prevention strategies are reviewed in detail.
Treatment Options
Which one of the following approaches would you find appropriate for these patients? Base your choice on the published literature, your own experience, recent guidelines, and other sources of information, as appropriate.
To aid in your decision making, each of these approaches is defended in the following short essays by experts in the prevention of HIV infection. Given your knowledge of the patients and the points made by the experts, which approach would you choose? Read the essays and then cast your vote.
· Option 1: Recommend Initiating PrEP
· Option 2: Do Not Recommend Initiating PrEP
Option 1 (0)
Option 2 (0)
Option 1
Recommend Initiating PrEP
Salim S. Abdool Karim, M.B., Ch.B., Ph.D.
The decision-making process for recommending PrEP begins with an assessment of the risk of HIV, followed by a determination of the combination of HIV-prevention strategies that provides the maximum protection. In the United States, men who have sex with men comprise approximately 2% of the population but account for more than 60% of new HIV infections. A history of sexually transmitted diseases and multiple partners places the man in the first vignette at high risk. Despite education and condom-promotion programs, young women are the highest-risk group in Africa, where the prevalence of HIV among women 20 years of age is as high as 26.7%.1 The fact that the young woman in the second vignette has had multiple partners places her at high risk in the generalized HIV epidemic in South Africa, where 12% of the population (approximately 5.6 million people) are HIV-infected. Her risk is higher if any partner is 5 or more years older than she is.
The effective options for HIV prevention that are available for the persons in both vignettes include the use of condoms, "sero-sorting" (choosing only partners who are HIV-negative), treatment for prevention (ensuring that all HIV-positive partners are taking antiretroviral treatment), and, finally, PrEP. Although medical circumcision of men is an established HIV-prevention option for heterosexual men, it has not yet been proven to be effective in protecting women2 or men who have sex with men.3 Although an HIV-prevention strategy that is based on knowing every partner's HIV status is desirable, this is rarely possible. Even partners who recently tested HIV-negative have a tangible risk, in high-incidence groups, of having an undiagnosed "window-period" infection or of having acquired HIV after the test was performed. Among HIV-positive partners who say they are receiving treatment, the risk of their transmitting the virus to others depends on their having actually initiated treatment, their adherence to treatment, and consequent viral suppression. In the case of young African women, who are seldom able to insist on the use of condoms or to establish the HIV status or treatment status of their partners, placing their risk of infection totally in the hands of their male partners is risky and fundamentally undermines efforts to empower women to control their own risk.
Hence, PrEP, which empowers receptive partners to control their HIV risk, is an essential component of an effective combination prevention strategy for the persons in both vignettes. In the absence of renal disease, daily treatment with tenofovir disoproxil fumarate (TDF) coformulated with emtricitabine (FTC), a therapy for which there are extensive safety data, should be prescribed, since it was shown to be effective in reducing HIV acquisition among men who have sex with men in the Preexposure Prophylaxis Initiative (iPrEX) trial4 and among heterosexual partners in the Partners PrEP5 and TDF26 trials. In these studies, drug resistance, which is a concern with the use of any antiretroviral agent, was an uncommon occurrence and was largely restricted to persons who initiated PrEP during an undiagnosed window-period infection. Nucleic acid testing (which tests for the presence of virus before antibodies can be detected) at the time of the initiation of PrEP, a costly option, could reduce the risk of resistance. For resistance that may still be present at the initiation of future treatment, effective therapeutic options other than TDF-FTC are available. It is important that PrEP be accompanied by counseling on the continued and increased use of condoms and on adherence to therapy, in order to avoid the lack of effectiveness that was observed in the Preexposure Prophylaxis Trial for HIV Prevention among African Women (FEM-PrEP).7
Widespread implementation of PrEP is, however, not without challenges that will require additional financial resources and health services capacity. Nevertheless, PrEP is an essential new HIV-prevention strategy that can and should be implemented in combination with the use of condoms, HIV testing, and promotion of treatments for HIV infection. PrEP prevents HIV infection, thereby reducing the need for treatment of AIDS in the future, is cost-effective,8 and empowers vulnerable populations to directly control their risk of HIV infection.
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