PARTNER’s Zero Transmissions

Indviduals living with HIV, engaged in care, and adherent to antiretroviral therapy to the point of suppressing the virus to an undetectable level can feel more confident in their health as well as their sexual lives, thanks to a new study. The PARTNER (Partners of People on ART—A New Evaluation of the Risks) study provides overwhelming evidence that the risk of an HIV-positive individual, with an undetectable viral load and engaging in condomless penetrative anal or vaginal sex, transmitting the virus to a HIV-negative sexual partner may really only be theoretical.

“The estimate of the overall transmission rate, and the transmission rate for anal sex, was zero. However, 95% confidence limits suggest that with eligible couple-years accrued so far, appreciable levels of risk cannot be excluded, particularly for anal sex and when considered from the perspective of a cumulative risk over several years,” states Alison J. Rodger, et al, in the article “Sexual Activity Without Condoms and Risk of HIV Transmission in Serodifferent Couples When the HIV-Positive Partner Is Using Suppressive Antiretroviral Therapy,” published in the July 12, 2016 edition of the Journal of the American Medical Association. Only eleven HIV-negative partners seroconverted to positive. However, it should be noted that these transmissions could not be linked back to the partners in the study. No phylogenetically linked transmissions occurred over eligible couple-years of follow-up.

The prospective, observational study, which took place across seventy-five clinical sites in fourteen European countries, enrolled 1,116 HIV serodifferent couples who reported condomless sex between September 2010 and May 2014, where the HIV-positive partner was on suppressive antiretroviral therapy and the negative partner was not on PrEP or had used PEP.

A total of 1,238 eligible, follow-up couple-years was provided from 548 heterosexual (36,000 condomless sex acts) and 340 MSM (22,000 condomless sex acts) couples. (Not all of the starting total of couples met the full criteria.) Couples reported condomless sex for a median of two years, at baseline. In addition, 108 HIV-negative MSM and twenty-one heterosexuals reported condomless sex with other partners. Longer follow-up data is needed to cull more specifics about risk, the researchers stated.