Changes in Condomless Sex and Serosorting Among Men Who Have Sex With Men After HIV Diagnosis.

BACKGROUND: Among men who have sex with men (MSM) diagnosed with HIV, high-risk sexual behaviors may decline in the year after diagnosis. The sustainability of these changes is unknown.
METHODS: We created a retrospective cohort (Seroconversion Cohort) of MSM attending an STD clinic in Seattle, Washington who tested HIV positive between 2001 and 2013 and had a negative HIV test <2 years before diagnosis. We randomly selected 1000 HIV-negative controls (men who always tested HIV negative) who were frequency-matched to the Seroconversion Cohort based on HIV diagnosis year. 12-month sexual behavior data were collected at each clinic visit. We examined condomless anal intercourse (CAI) with HIV-negative, HIV-positive, and HIV unknown-status partners before diagnosis and up to 4 years thereafter.
RESULTS: Of the 26,144 clinic visits where MSM tested for HIV, there were 655 (2.5%) new HIV diagnoses. Of these, 186 (28%) men had previously tested HIV negative and were included in the Seroconversion Cohort. The proportion (of the 186) reporting CAI with HIV-negative partners declined from 73% at diagnosis to 12% after diagnosis (P < 0.001), whereas CAI with HIV-positive partners increased (11%-67%; P < 0.001). The proportion who serosorted (ie, CAI only with HIV-concordant partners) did not change before or after diagnosis (34%-40%; P = 0.65). These 3 behaviors remained stable for up to 4 years after diagnosis. Among HIV-negative controls, serosorting and CAI with HIV-positive and HIV-negative partners was constant.
CONCLUSIONS: MSM substantially modify their sexual behavior after HIV diagnosis. These changes are sustained for several years and may reduce HIV transmission to HIV-uninfected men.