WHO Guidelines Address Preexposure Prophylaxis for HIV

Laurie Barclay, MD

July 23, 2012

July 23, 2012 — New World Health Organization (WHO) guidelines address preexposure prophylaxis (PrEP), or prophylactic use of antiretroviral agents by people who are HIV-negative but who are at risk for infection.

"The field of HIV prevention, until recently, experienced years of disappointment, as the search for potential vaccines and non-antiretroviral microbicides has yielded little result," the WHO guidelines state. "Now, however, a promising new approach has emerged: the use of antiretroviral drugs for HIV prevention, both for those uninfected and for those already living with HIV.

"These recommendations have been developed specifically to address the daily use of antiretrovirals in HIV-uninfected people to block the acquisition of HIV infection," the WHO writes.

Worldwide prevalence of HIV infection is 34 million, with 2.7 million new cases in 2010 alone. Despite stabilization of the rate of new infections in some countries, there is an urgent need for safe and effective preventive strategies. Currently available, partially effective approaches have included male and female condoms, male circumcision, prevention of mother-to-child HIV transmission, and provision of sterile injecting equipment and opiate substitution therapy for injection drug users.

The guidelines highlight 2 specific recommendations for PrEP:

  1. Daily oral PrEP (with tenofovir alone or with the combination of tenofovir and emtricitabine) may be considered as a possible additional intervention for the uninfected partner of an HIV-serodiscordant heterosexual couple. Settings in which PrEP should specifically be considered are countries in which HIV transmission occurs among serodiscordant couples, in which discordant couples can be identified, and in which additional HIV prevention choices are needed. This is a conditional recommendation with high quality of underlying evidence.

  2. Daily oral PrEP with the combination of tenofovir and emtricitabine may be considered a possible additional intervention when additional HIV prevention choices are needed in countries in which HIV transmission occurs among men and transgender women who have sex with men. This is also a conditional recommendation with high quality of underlying evidence.

Recommendations for Demonstration Projects

The guidelines recommend that countries intending to implement oral PrEP should begin demonstration projects to determine the most suitable target groups and strategies for intervention delivery. Specific suggestions include the following:

  • determine that persons requesting PrEP are actually HIV-negative, which should minimize development of drug resistance;

  • stress the importance of continued condom use, treatment of sexually transmitted infections, and other prevention measures among persons given PrEP;

  • rule out medical comorbidities, such as renal or bone disease, which would contraindicate use of ARVs;

  • monitor for development of adverse events, such as possible mild decreases in bone mineral density and renal functioning;

  • facilitate adherence to the daily dosing regimen required for PrEP;

  • ensure availability of PrEP medications provided at a convenient time and place;

  • monitor for development of HIV infection in persons taking PrEP (although the optimal interval for periodic retesting is still unclear), and for drug resistance in those who become infected;

  • ensure continued availability of other HIV prevention services to persons who discontinue PrEP; and

  • determine cost-effectiveness of PrEP to prioritize allocation of limited resources.

Underlying Evidence

Clinical trials have shown that in most HIV-negative persons, daily use of oral antiretroviral medication for PrEP is safe and effective for HIV prevention. In the Pre-Exposure Prophylaxis Initiative (iPrEX) study, use of PrEP was associated with a 40% reduction in HIV infection among men who have sex with men. With adherence to the daily dosing regimen, this reduction increased up to 73%.

Among serodiscordant couples in Kenya and Uganda, PrEP reduced new infections by 75%, according to findings from the Partners PrEP study.

According to findings from the demonstration projects, as well as evolving scientific evidence, the WHO plans to issue consolidated guidelines on antiretroviral use to prevent and treat HIV infection. The new recommendations should be available in the summer of 2013.

The US Food and Drug Administration recently approved antiretroviral use as part of a comprehensive HIV prevention strategy including condom use, other safe sex practices, HIV testing, and behavioral counseling. Anticipated cost of the antiretroviral used for PrEP is $13,900 per person per year.

Four members of the Guidelines Development Group and the External Review Group have declared potential conflicts of interest, but none of these were deemed significant by the WHO Steering Group.

"Guidance on Oral Pre-Exposure Prophylaxis (PrEP) for Serodiscordant Couples, Men and Transgender Women Who Have Sex With Men at High Risk of HIV: Recommendations for Use in the Context of Demonstration Projects." WHO.

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