A randomized noninferiority trial of standard versus enhanced risk reduction and adherence counseling for individuals receiving post-exposure prophylaxis following sexual exposures to HIV.

Abstract

The National HIV/AIDS Strategy proposes to scale-up post-exposure prophylaxis (PEP). Intensive risk reduction and adherence counseling appear to be effective but are resource intensive. Identifying simpler interventions that maximize the HIV prevention potential of PEP is critical. A randomized noninferiority study comparing 2 (standard) or 5 (enhanced) risk reduction counseling sessions was performed. Adherence counseling was provided in the enhanced arm. We measured changes in unprotected sexual intercourse acts at 12 months, compared with baseline; HIV acquisition; and PEP adherence. Outcomes were stratified by degree of baseline risk. We enrolled 457 individuals reporting unprotected intercourse within 72 h with an HIV-infected or at-risk partner. Participants were 96% male and 71% white. There were 1.8 and 2.3 fewer unprotected sex acts in the standard and enhanced groups. The maximum potential risk difference, reflected by the upper bound of the 95% confidence interval, was 3.9 acts. The difference in the riskier subset may have been as many as 19.6 acts. The incidence of HIV seroconversion was 2.9% and 2.6% among persons randomized to standard and enhanced counseling, respectively, with a maximum potential difference of 3.4%. The absolute and maximal HIV seroconversion incidence was 9.9% and 20.4% greater in the riskier group randomized to standard, compared with enhanced, counseling. Adherence outcomes were similar, with noninferiority in the lower risk group and concerning differences among the higher-risk group. Risk assessment is critical at PEP initiation. Standard counseling is only noninferior for individuals with lower baseline risk; thus, enhanced counseling should be targeted to individuals at higher risk.