Background
Pre-exposure prophylaxis (PrEP) is an effective tool for HIV prevention, but its adoption has varied significantly. Monitoring trends in HIV incidence, PrEP utilization, and the PrEP-to-Need Ratio (PnR—i.e., the ratio of PrEP users to new HIV cases) can provide critical insights into the effectiveness of HIV prevention efforts and identify areas and populations requiring improved interventions. However, trends on these outcomes are limited. This study examined trends in HIV incidence rate, PrEP utilization rate, and PnR in the United States.

Methods
This study used AIDSVu state-level cross-sectional study data from 2013–2023, sourced from state and local health departments in all 50 states and the District of Columbia. Outcome variables included HIV incidence rate, PrEP utilization rate, and PnR. HIV incidence and PrEP utilization rates were calculated using number of new diagnoses cases and PrEP users data, respectively. Descriptive statistics and geospatial visualization were performed using SAS v. 9.4 and ARCGIS Pro v. 3.4, respectively.

Results
The national HIV incidence rate declined slightly from 12 cases per 100,000 in 2013 to 11 cases per 100,000 in 2022 (2023 incidence data unavailable), with Washington D.C., Georgia, Florida, Louisiana, Texas, and Nevada reporting the highest rates in 2022. The national PrEP utilization rate showed a significant increase from 3 users per 100,000 population in 2013 to 153 users per 100,000 in 2023. The mean PnR improved markedly from 0.4 (Standard Deviation [SD] = 0.5) in 2013 to 20.9 (SD = 23.8) in 2023, with Vermont, New Hampshire, Montana, Washington D.C., and Massachusetts reporting the highest PnR in 2023. Among males, the mean PnR increased from 0.4 (SD = 0.5) in 2013 to 24.1 (SD = 28.4) in 2023, while among females, it rose from 0.8 (SD = 1.2) in 2013 to 8.4 (SD = 10.7) in 2023.

Conclusion
The slight decrease in HIV incidence and notable increases in the PrEP utilization rate and PnR across the study period highlight progress in HIV prevention efforts in the U.S. However, persistent disparities across states and gender groups indicate the need for targeted interventions to address gaps in PrEP utilization and ensure equitable coverage nationwide.