Projected Impact of Expanded Long-Acting Injectable PrEP Use Among Men Who Have Sex With Men on Local HIV Epidemics.

Background: Pre-exposure prophylaxis (PrEP) is a key component in helping to reduce HIV incidence in the United States. Long-acting injectable (LAI) PrEP is a new alternative to oral PrEP; its potential to affect local HIV epidemics remains unclear.

Methods: The Johns Hopkins HIV Economic Epidemiological model (JHEEM) is a dynamic model of HIV transmission in 32 US urban areas. We used JHEEM to project the HIV incidence among men who have sex with men (MSM) from 2020 to 2030 under a range of interventions aimed at increasing PrEP use.

Results: In the absence of any intervention (ie, current levels of oral PrEP and HIV care engagement), we projected a 19% reduction (95% credible interval, CrI 1% to 36%) in HIV incidence among MSM from 2020 to 2030 across all 32 cities. Adding 10% LAI PrEP uptake (above a base case of all oral PrEP) reduced the incidence by 36% (95% CrI 23% to 50%) by year 2030. This effect varied between cities, ranging from 22% in Atlanta to 51% in San Francisco. At 25% additional LAI PrEP uptake, this incidence reduction increased to 54% (95% CrI 45% to 64%). Reductions in incidence after introducing LAI PrEP were driven primarily by increased uptake and sustained usage rather than increased efficacy.

Conclusions: LAI PrEP has the potential to substantially reduce HIV incidence among MSM, particularly if it increases PrEP uptake and continued use beyond existing levels. Because potential effects vary by city, the effectiveness of expanding PrEP use is dependent on local dynamics.