HIV Post-Exposure Prophylaxis Following Sexual Exposure (PEPSE)

Last edited 03/2018

HIV Post-Exposure Prophylaxis Following Sexual Exposure (PEPSE)

Studies on pathogenesis of HIV have reported regarding a window of opportunity to avert the infection by inhibiting viral replication following an exposure.

• once the virus crosses a mucosal barrier, it may take up to 48 -72 hours before HIV can be detected within regional lymph nodes and up to five days before HIV can be detected in blood
• in animal models, initiation of antiretroviral therapy soon after inoculation resulted in reduce dissemination and replication of virus in all tissues (1)

Data supporting the use of post exposure prophylaxis (PEP) against HIV:

• animal studies
• animal studies suggest that PEP can be potentially effective and that time to initiation and duration are important
• two studies demonstrated effectiveness of subcutaneous PMPA (tenofovir) in macaque models following intravenous simian immunodeficiency virus (SIV) or intravaginal HIV-2 inoculation
• efficacy was highest if PEP was administered within 24-36 hours and continued for 28 days
  
  
• human studies
• a retrospective case-controlled study among health-care workers occupationally exposed to HIV infection demonstrated that a 28-day course of zidovudine was protective, odds ratio (OR) 0.19 (95% confidence interval (CI) 0.06 -0.52%)
• however there are also instances where PEP has failed to prevent HIV infection following occupational exposure
• in a subset of women in the AIDS Clinical Trials Group (ACTG) 076 study who did not receive zidovudine prior to delivery but where the neonate was given a six-week course of zidovudine, initiated within 48 hours of delivery, a protective effect was observed (1)

Note:

• Post-Exposure Prophylaxis Following Sexual Exposure (PEPSE) should not be considered or encouraged as a first line method of HIV prevention (1)

Reference:

• (1) https://www.bashh.org/documents/PEPSE%202015%20guideline%20final_NICE.pdf