HIV incidence and related risks among gay, bisexual, and other men who have sex with men in Montreal, Toronto, and Vancouver: Informing blood donor selection criteria in Canada.

BACKGROUND: An individualized behavior-based selection approach has potential to allow for a more equitable blood donor eligibility process. We collected biological and behavioral data from urban gay, bisexual, and other men who have sex with men (GBM) to inform the use of this approach in Canada.

STUDY DESIGN AND METHODS: Engage is a closed prospective cohort of sexually active GBM, aged 16+ years, recruited via respondent-driven-sampling (RDS) in Montreal, Toronto, and Vancouver, Canada. Participants completed a questionnaire on behaviors (past 6 months) and tested for HIV and sexually transmitted and blood-borne infections at each visit. Rate ratios for HIV infection and predictive values for blood donation eligibility criteria were estimated by RDS-adjusted Poisson regression.

RESULTS: Data on 2008 (study visits 2017-02 to 2021-08) HIV-negative participants were used. The HIV incidence rate for the three cities was 0.4|100 person-years [95%CI:0.3, 0.6]. HIV seroconversion was associated with age <30 years: adjusted rate ratio (aRR) 9.1 [95%CI:3.2, 26.2], 6-10 and >10 anal sex partners versus 1-6 aRR: 5.3 [2.1,13.5] and 8.4 [3.4, 20.9], and use of crystal methamphetamine during sex: 4.2 [1.5, 11.6]. Applying the combined selection criteria: drug injection, ≥2 anal sex partners, and a new anal sex partner, detected all participants who seroconverted (100% sensitivity, 100% negative predictive value), and would defer 63% of study participants from donating.

CONCLUSION: Using three screening questions regarding drug injection and sexual behaviors in the past 6 months would correctly identify potential GBM donors at high risk of having recently contracted HIV. Doing so would reduce the proportion of deferred sexually active GBM by one-third.