A behavioral cascade of HIV seroadaptation among US men who have sex with men in the era of PrEP and U=U

ABSTRACT Seroadaptive behaviors help to reduce HIV risk for some men who have sex with men (MSM), and have been well documented in a range of MSM populations. Advancements in biomedical prevention have changed the contexts in which seroadaptive behaviors occur. We thus sought to estimate and compare the prevalence of four stages of the “seroadaptive cascade” in the recent era: knowledge of own serostatus, knowledge of partner serostatus; serosorting (matching by status), and condomless anal intercourse. Serosorting overall appeared to remain common, especially with casual and one-time partners. Although PrEP use did not impact status discussion, it did impact serosorting and the likelihood of having condomless anal intercourse. For respondents not diagnosed with HIV and not on PrEP, condomless anal intercourse occurred in just over half of relationships with partners who were not on treatment. Biomedical prevention has intertwined with rather than supplanted seroadaptive behaviors, while contexts involving neither persist.