ABSTRACT
Background HIV preexposure prophylaxis (PrEP) could reduce the disparities in HIV incidence among black men who have sex with men (BMSM) compared to white MSM (WMSM), but this may depend on progression through the PrEP care continuum.
Methods We expanded our network-based mathematical model of HIV transmission for MSM, which simulates PrEP based on CDC’s clinical practice guidelines, to include race-stratified transitions through the PrEP continuum steps of awareness, access, prescription, adherence, and retention. Continuum parameters were estimated based on published incidence cohorts and PrEP open-label studies. Counterfactuals included a no-PrEP reference scenario, and intervention scenarios in which the BMSM continuum step parameters were modified.
Results Implementing PrEP according to the observed BMSM continuum was projected to result in 8.4% of all BMSM on PrEP at year 10, yielding a 23% decline in incidence (HR = 0.77). On an absolute scale, the racial disparity in incidence in this scenario was 4.95 per 100 person-years at risk (PYAR), a 19% decline from the 6.08 per 100 PYAR disparity in the reference scenario. If BMSM continuum parameters were equal to WMSM values, 17.7% of BMSM would be on PrEP, yielding a 47% decline in incidence (HR = 0.53) and a disparity of 3.30 per 100 PYAR (a 46% decline in the disparity).
Conclusions PrEP could lower HIV incidence overall and reduce absolute racial disparities between BMSM and WMSM. Interventions addressing the racial gaps in the PrEP continuum will be needed to further decrease these HIV disparities.