Rodger AJ, et al. - In the second phase of the PARTNER study (PARTNER2), researchers sought to produce a similar level of evidence for transmission risk through condomless anal sex among men with suppressive antiretroviral therapy (defined as HIV-1 RNA viral load <200 copies per mL) to that generated for heterosexual couples in PARTNER1. They included 972 couples (477 couples during PARTNER1) between September 15, 2010 and July 31, 2017. The outcomes give a similar level of evidence on gay men's viral suppression and risk of HIV transmission as previously generated for heterosexual couples. The risk of condomless sex transmission of HIV in gay couples when HIV viral load is suppressed is essentially zero. The study findings support the U=U (undetectable equals untransmittable) campaign message, as well as the benefits of early HIV testing and treatment.