WHO Simplifies Advice on HIV Post-Exposure Prophylaxis

December 01, 2014

The World Health Organization (WHO) today marked World AIDS Day by issuing simpler guidelines for HIV prophylaxis after someone is exposed to the virus through the likes of unprotected sex with an infected person or a blood splash in the eye.

WHO's previous recommendations on post-exposure prophylaxis (PEP) from 2007 focused on adults following either an occupational exposure — in a healthcare setting, for example — or a sexual assault. The standard treatment consisted of two antiretrovirals (ARVs), with a third added if there was ARV resistance in the patient or the local community.

In its new guidelines, WHO recommends three ARVs across the board, regardless of how the exposure occurred. This regimen eliminates the need to ferret out information on drug resistance, which requires less expertise on the part of healthcare workers — an important consideration in less developed nations — and speeds up treatment. A three-drug cocktail for PEP also parallels the standard use of three ARVs for those infected with HIV, further simplifying matters.

In the case of adults and adolescents needing PEP, WHO recommends starting with a "backbone" of tenofovir disoproxil fumarate and either lamivudine or emtricitabine. Antiretroviral therapy (ART) also favors the use these two drugs. The choice of a third ARV for PEP is less clear, owing to a dearth of good studies, according to WHO. The agency prefers lopinavir/ritonavir or atazanavir/ritonavir "because these drugs are currently recommended for use in ART and relatively widely available in low and middle income countries."

WHO noted that the development of less toxic, better tolerated ARVs makes a three-drug approach feasible. "Although the addition of a third drug increases the potential for drug-related toxicity, reported (PEP) completion rates are similar comparing two and three-drug regimens," WHO stated.

New Guidance on Cotrimoxazole Prophylaxis

WHO also has updated its recommendations on cotrimoxazole prophylaxis for opportunistic infections related to HIV.

Cotrimoxazole has long been used to prevent and treat a range of bacterial, fungal, and protozoan infections in individuals with HIV. Originally, WHO guidance on cotrimoxazole prophylaxis focused on people with advanced HIV infections and limited access to antiretrovirals. However, WHO has come to recognize a "broader benefit" in cotrimoxazole — preventing malaria and several bacterial infections in patients with HIV regardless of their CD4 count.

Accordingly, WHO now recommends cotrimoxazole prophylaxis for adults at any stage of HIV infection who live in areas where malaria and severe bacterial diseases are highly prevalent. With infants, children, and adolescents with HIV in all settings, clinicians should begin cotrimoxazole prophylaxis as soon as possible.

More information on WHO's updated guidelines are available on the agency's website.


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