Over the course of two years, the study tracked 888 serodiscordant couples — that is, couples in which one partner is HIV-positive and one is HIV-negative. This included 548 different-sex couples and 340 same-sex male couples. The HIV-positive partners maintained undetectable viral levels with antiretroviral therapy (ART), but the HIV-negative partners did not use PrEP.
There were 11 cases in the study in which partners contracted HIV, but they didn’t get it from their partners. Researchers tested the virus in each case and confirmed that what they had contracted was not phylogenetically linked to their partners’ virus. In other words, it was conclusively proven that they only contracted HIV because they had sex outside the relationship.
Simon Collins, a member of the PARTNER study steering committee, described the results as “simple to understand.” In a statement, he explained, “This provides the strongest estimate of actual risk of HIV transmission when an HIV positive person has undetectable viral load — and that risk is effectively zero.”The implications of this result for public policy around HIV stigmatization in the United States are profound. There are numerous HIV-positive Americans who are serving draconian criminal sentences for having sex with other people due to misguided laws (combined with overzealous prosecutions and bigoted juries). Oftentimes, it is people of color who are disproportionately impacted, as exemplified by one of the most (in)famous of these cases, the so-called "Tiger Mandingo" case where a 23-year-old African-American man named Michael Johnson was sentenced to 30 years in jail after being convicted of multiple felonies in Missouri.
Hopefully, this new scientific evidence from the PARTNER study can be used to help organizations like the SERO Project support the repeal of some of these pernicious laws around the country.