Essentially zero risk of HIV transmission from men who take antiretroviral therapy

Reference

Rodger AJ, Cambiano V, Bruun T, et al, for the PARTNER Study Group. Risk of HIV transmission through condomless sex in serodifferent gay couples with the HIV-positive partner taking suppressive antiretroviral therapy (PARTNER): final results of a multicentre, prospective, observational study. Lancet 2019;393(10189):2428-2438.

Synopsis

These researchers recruited 972 male couples who had discordant HIV status, engaged in condomless sex, and the HIV-infected partner was taking antiretroviral therapy (ART). The researchers collected data (HIV, viral load, CD4 counts, and so forth) at the time of enrollment and then every 4 months to 6 months thereafter. If the HIV-negative partner converted, the authors performed sequencing to determine if the transmission was linked to the partner. After a median of 2 years of follow-up, the researchers lost approximately 25 per 100 couple-years of data, mostly due to the disintegration of the relationship. Additionally, the researchers excluded approximately one third of the participants from the analysis because they did not report having condomless sex during the study period. Finally, they excluded couples in which the seronegative partner used pre-exposure prophylaxis. Nearly all the HIV-positive men who were taking ART (96%) had less than 50 HIV-1 RNA copies per mL and the remainder had between 50 and 200 copies per mL. Self-reported adherence to ART was well over 90% and only 5% reported missing ART for 4 or more consecutive days. During the follow-up period, approximately 25% of the men reported having developed other sexually transmitted infections. Additionally, 37% of HIV-negative men reported having condomless sex with other partners. Couples had condomless sex a median of 43 times per year. The researchers collected detailed information about sexual practices (insertive vs receptive condomless anal intercourse, receptive anal intercourse with or without ejaculation, and so forth). Overall, only 15 men developed new HIV infections and none were transmitted by their partner. So, the overall HIV transmission rate was 0 (95% CI 0 - 0.23 per 100 couple-years of follow-up). These data are comparable with HIV transmission rates among HIV-discordant heterosexual couples.