HIV / STI
Assessing the Impact of Population-Level Interventions on HIV Transmission Among Heterosexual African American/Black People: A Spatially Dynamic Agent-Based Modeling Study Shayla Nolen* Shayla Nolen Sam E. Bessey Katie B. Biello Bridgette M. Brawner Rice Akilah Dulin Chanelle J. Howe Brandon D. L. Marshall
Objectives: To assess the impact of population-level interventions on HIV transmission among heterosexual African American/Black people using a spatially dynamic, agent-based model.
Methods: We simulated a population of 130,565, hereby referred to as agents, representing the number of heterosexual African American/Black people who were living with diagnosed HIV or at risk for HIV in Philadelphia in 2019 in a spatially dynamic agent-based model. Agents in the model were assigned probabilities of engaging in unprotected sex with casual and main partners, spatially assortative mixing (i.e., the likelihood of selecting a sexual partner in an adjacent census tract [CT]), progression through the HIV care continuum (HCC), and incarceration based on their CT of residence and whether the CTs was more or less disadvantaged. We determined the CT’s disadvantage status by creating a composite score that was dichotomized at the median. We tested the following interventions: opt-out testing, culturally congruent HCC interventions, criminal justice reform, and a combination of all the aforementioned interventions. For each intervention scenario, we compared the percentage reduction in new HIV diagnoses between 2019 and 2030 to the base case scenario (i.e., the current status quo).
Results: The relative percent reduction of the base case and all standalone interventions resulted in a 29-31% reduction. The combination intervention scenario resulted in a slightly larger relative decrease in new HIV diagnoses by 2030 at 34.2%.
Conclusion: Combinations of interventions that address structural factors that contribute to HIV transmission, such as incarceration and improved progression through the HCC, can make a more meaningful impact on reducing HIV transmission than interventions that solely address testing and treatment. However, the observed effects in this simulation study were small, suggesting that a high proportion of transmission may be due to other unmeasured structural factors.