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Published: Tuesday, 30 June 2015 14:26

Written by 340B Editor

In December 2014, The World Health Organization (WHO) published a new supplemental guideline for post-exposure prophylaxis (PEP) for persons who may have been exposed to HIV. This new guideline has erased the distinction between occupational and non-occupational settings where a person may have been exposed to HIV, and has instead focused on preferred treatment regimens that apply to all possible exposed persons so as to simplify care for all patients put at risk for HIV.

Ignoring the setting where the possible exposure occurred, there are still recommendations for which types of exposures would require PEP and which would not. Exposures of infected (or possibly infected) bodily fluids to the mucous membranes (splashes to the eye, nose, or oral cavity and sexual exposure) or parenteral exposures always require PEP. Potentially dangerous bodily fluids include blood, bloody saliva, breast-milk, genital secretions, and cerebrospinal, amniotic, rectal, peritoneal, synovial, pericardial, or pleural fluids. Exposures that would not warrant PEP would be when the exposed person is already HIV positive, if the source is proven to be HIV negative, or if the exposure was to bodily fluids that are considered low risk for transmission (tears, non-bloody saliva, urine, or sweat).

Once it has been established that the exposed person is in need of PEP, the treatment should begin as soon as possible. PEP can decrease the risk of HIV infection by over 80%, and timely treatment initiation is very important to its success. Ideally, this treatment should begin within 72 hours of exposure, but a patient presenting after this time can still receive PEP, knowing that the chance of preventing transmission has decreased. Determining the HIV status of both the exposed and the source persons should be undertaken as soon as possible, but should not delay treatment. If the source is determined to be HIV negative, PEP can always be discontinued later.

WHO states that an effective anti-retroviral medication treatment should be continued for 28 days, and they prefer a regimen with three drugs instead of two. Two drug regimens are still considered effective, and may be preferred in some circumstances, however with three drugs resistance is less of a concern, toxicities have been limited with the development of new drugs, and PEP completion rates has been shown to be similar as with two drugs. Adopting a three drug regimen for all patients for PEP will simplify prescribing as well. The WHO preferred regimen for adults and adolescents includes tenofovir and emtricitabine as the backbone with either lopinavir/ritonavir or atazanavir/ritonavir as the third drug. Alternative options include raltegravir, darunavir/ritonavir, or efavirenz where available. The third drug can be any of these options and the final choice for each patient should be based on cost, availability, side effect profiles, and ease of use. Lopinavir/ritonavir and atazanavir/ritonavir were preferred by WHO because they are recommended for use in antiretroviral therapy (ART) and are often available in low and middle income countries. Efavirenz, though recommended for first-line ART, may not be the best option for PEP due to early nervous system and mental side effects that make its use in potentially HIV negative patients questionable.

Any individual who has been potentially exposed to HIV should have follow up HIV testing 3 months after the event. Further testing may be necessary for someone who tests negative if they are continually involved in high risk behavior, can identify a specific possible exposure in the past 3 months, are pregnant and living in a HIV epidemic setting, or have an indeterminate HIV status. Anyone testing positive should be connected with treatment and care services as soon as possible. Patients taking PEP should also be counseled on how to prevent possible transmission to others, including the use of condoms, safe-injection processes, and not giving blood donations until they have completed their PEP regimen and the risk of transmission has passed.

1. Guidelines on post-exposure prophylaxis for HIV and the use of co-trimoxazole prophylaxis for HIV-related infections among adults, adolescents and children: recommendations for a public health approach.” World Health Organization, Geneva. December 2014.