New HIV Infections Among MSM Where Antiretroviral Therapy Coverage Is High

Increasing use of antiretroviral therapy (ART) among men who have sex with men (MSM) has not substantially reduced the incidence of new HIV infections in many developed countries, despite ART's undisputed effectiveness in reducing rates of HIV transmission. To explore why, investigators in the Netherlands used viral-phylogenetic and clinical data from the ATHENA observational cohort, involving more than 13,000 MSM, to reconstruct transmission events from July 1996 through December 2010.

Of 617 recent transmissions, an estimated 71% occurred from undiagnosed men, 22% from men who had been diagnosed but not yet treated, 6% from men who had initiated ART but had not yet achieved viral suppression, and 1% from men who lacked contact with care fo…