An application of agent-based modeling to explore the impact of decreasing incarceration rates and increasing drug treatment access on sero-discordant partnerships among people who inject drugs.

BACKGROUND: People who inject drugs (PWID) lag behind other key populations in HIV care continuum outcomes. The impacts of criminal justice reform and increasing drug treatment access on HIV have been underexplored. METHODS: We developed agent-based models (ABM) of sexual partnerships among PWID and non-PWID, and injection equipment-sharing partnerships among PWID in five US cities (Baltimore, Boston, Miami, New York City, San Francisco) over 3 years. The first set of ABM projected changes in partnership discordance among PWID as a function of decreasing ZIP code-level incarceration rates. The second set projected discordance as a function of increasing ZIP code-level drug treatment access. ABM were parameterized and validated overall, and by city and PWID race/ethnicity (Black, Latino, White) using National HIV Behavioral Surveillance data, administrative ZIP code-level data, surveillance reports and prior literature. Informed by research on prisoner release and community-level HIV prevalence, reductions in incarceration rates were fixed at 5% and 30% and respectively projected to increase ZIP code-level HIV prevalence by 2% and 12%. Increases in drug treatment access were fixed at 30% and 58%. RESULTS: In each city, a 30% reduction in ZIP code-level incarceration rates and 12% increase in ZIP code-level HIV prevalence significantly increased sero-discordance among at least one racial/ethnic group of PWID by 1-3 percentage points. A 5% reduction in incarceration rates, and 30% and 58% increases in drug treatment access, led to isolated significant changes in sero-discordance among Black and White PWID that were less than 1 percentage point. CONCLUSION: Reductions in incarceration rates may lead to short-term increases in sero-discordant partnerships among some PWID by increasing community-level HIV prevalence. Efforts to increase HIV testing, engagement in care and community reintegration post release, should be strengthened in the wake of incarceration reform. Additional research should confirm these findings and explore the lack of widespread impacts of drug treatment in this study.

HIV Among MSM and Heterosexual Women in the United States: An Ecologic Analysis.

BACKGROUND: Phylogenetic studies show links between heterosexual women and men who have sex with men (MSM) that are more numerous than from heterosexual men to women suggesting that HIV infections among heterosexual women may stem from MSM. Poor communities have been associated with high rates of HIV among heterosexual women. Our analysis investigates potential transmission of HIV between MSM and female heterosexuals. METHODS: National HIV Behavioral Surveillance data describe transmission risk behaviors of MSM, and HIV case reporting data describe the percentages of cases that are attributed to transmission risk categories. We examined correlations between the percentages of men who were MSM who also have sex with women and female heterosexual cases. We also examined census data to characterize each city in terms of poverty level and race/ethnicity makeup. RESULTS: There was a high correlation (0.93) between the percentage of reported living HIV cases attributed to male heterosexual contact and female heterosexual contact and a moderate nonsignificant correlation (0.49) between the percentage of MSM who were men who have sex with men and women (MSMW) in National HIV Behavioral Surveillance and the percentage of reported cases that were attributed to female heterosexual contact suggesting some potential overlap. Cities with high levels of poverty and African American/Black residents had higher levels of MSMW and higher levels of heterosexual female cases. CONCLUSIONS: Addressing HIV in cities with high levels of MSMW may have the dual effect of improving the health of MSM populations that have a high burden of HIV and to improve the health of their larger communities.