HIV: Post Exposure Prophylaxis (PEP) in nonoccupational settings

Dear Ask The Doctor: I topped an HIV postive male bareback, started on PEP meds within the 72 hour period, whats my chances of getting HIV??

Dear Robert: The use of PEP (post exposure prophylaxis) is an attempt to take advantage of the natural course of HIV infection. It is generally understood that the virus circulates within the body for up to 5 days following exposure before establishing itself within the CD4⁺ cells and lymphoid system. It is believed that this early period provides an opportunity to prevent or limit viral replication so that infection cannot take place. Some research studies have estimated the per-episode risk of HIV transmission from receptive anal intercourse and receptive vaginal intercourse is about 0.1% to 0.3% and 0.1% to 0.2% per episode, respectively. There are factors that elevate the degree of risk in sexual exposure as follows:  local trauma and the presence of blood, an abrasion, or a sexually transmitted disease associated lesion. It is important to have a negative HIV baseline test result before to initiate PEP after a nonoccupational exposure. PEP is not “a morning after pill” and if you are not committed to primary prevention and practices of safe sex, then you are not considered as a good candidate for PEP and you will be also contributing with the development of Resistance to the HIV drugs by the HIV. Delay to start PEP longer than 72 hours results in ineffective prophylaxis. PEP initiated within a few hours of exposure is the most effective. A course of PEP involves 28 days of a 2 or 3 drug treatment. However, the use of PEP for nonoccupational exposure remains experimental, and no guidelines currently exist for its implementation. Please, try to keep in mind that PEP cannot replace safer sex practices for those whose sexual activities include multiple partners, HIV-infected partners, or anonymous partners.