When effective post-exposure prophylaxis of HIV infection fails - Data from clinical practice

Abstract

Human immunodeficiency virus (HIV) prophylaxis with antiretroviral treatment after sexual exposure (sPEP) is an effective and safe approach; however, its influence on future exposures and, consequently, future HIV status remains under-investigated. We have evaluated the medical records of persons who received antiretroviral drugs (ARVs) as sPEP in the years 2009-2013. Cox proportional hazard models were used to identify predictors of having sexual exposure after finalising sPEP with HIV-negative status. In total 98 persons received sPEP: 37 (38%) after unprotected men who have sex with men (MSM) intercourse, 38 (39%) after sexual assault, and 23 (23%) after unprotected vaginal intercourse. In 40 (41%) cases the partner was HIV positive. Twelve persons (12%) repeated the same pattern of exposure; median time to next exposure was 1.55 (IQR 0.78-2.43) months. In multivariate Cox models older age was increasing, and heterosexual orientation decreasing the risk of having another exposure (HR = 1.06 [95% CI: 1.00-1.12; p = 0.033] and HR = 0.14 [95% CI: 0.02-1.06; p = 0.057], respectively). There were no HIV infections after completing sPEP, but three (3%) persons had occasional sexual contact afterwards, resulting in HIV infection. Median time from last negative exposure to HIV infection was 1.85 (IQR 1.79-2.43) months. In a considerable proportion of persons sPEP had no effect on behavioural patterns, mostly in those having occasional sexual contact. The risk of having another sexual exposure was higher with age and for MSM patients. For this group of persons pre-exposure prophylaxis may be a more viable method of HIV infection prophylaxis.