Epidemiology of HIV in the USA: epidemic burden, inequities, contexts, and responses

The HIV epidemic in the USA began as a bicoastal epidemic focused in large cities but, over nearly four decades, the epidemiology of HIV has changed. Public health surveillance data can inform an understanding of the evolution of the HIV epidemic in terms of the populations and geographical areas most affected. We analysed publicly available HIV surveillance data and census data to describe: current HIV prevalence and new HIV diagnoses by region, race or ethnicity, and age; trends in HIV diagnoses over time by HIV acquisition risk and age; and the distribution of HIV prevalence by geographical area. We reviewed published literature to explore the reasons for the current distribution of HIV cases and important disparities in HIV prevalence. We identified opportunities to improve public health surveillance systems and uses of data for planning and monitoring public health responses. The current US HIV epidemic is marked by geographical concentration in the US South and profound disparities between regions and by race or ethnicity. Rural areas vary in HIV prevalence; rural areas in the South are more likely to have a high HIV prevalence than rural areas in other US Census regions. Ongoing disparities in HIV in the South are probably driven by the restricted expansion of Medicaid, health-care provider shortages, low health literacy, and HIV stigma. HIV diagnoses overall declined in 2009-18, but HIV diagnoses among individuals aged 25-34 years increased during the same period. HIV diagnoses decreased for all risk groups in 2009-18; among men who have sex with men (MSM), new diagnoses decreased overall and for White MSM, remained stable for Black MSM, and increased for Hispanic or Latino MSM. Surveillance data indicate profound and ongoing disparities in HIV cases, with disproportionate impact among people in the South, racial or ethnic minorities, and MSM.