Estimating HIV incidence, prevalence, and undiagnosed infection in the United States

Anna Satcher-Johnson, M.P.H. & Rick Song, Ph.D.
Centers for Disease Control and Prevention

ABSTRACT:

The burden of HIV infection and health outcomes for people living with HIV varies across the United States. New methods allow for estimating national and state-level HIV incidence, prevalence, and undiagnosed infections using surveillance data and CD4 values. 

Methods: HIV surveillance data reported to the Centers for Disease Control and Prevention and the first CD4 value after diagnosis were used to estimate the distribution of delay from infection to diagnosis based on a well-characterized CD4 depletion model. This distribution was used to estimate HIV incidence, prevalence, and undiagnosed infections during 2010–2014. Estimated annual percentage changes were calculated to assess trends. 

During 2010–2014, HIV incidence decreased 10.3% (EAPC = -3.1%) and the percentage of undiagnosed infection decreased from 17.1% to 15.0% (EAPC = -3.3%) in the United States; HIV prevalence increased 9.1% (EAPC = 2.2%). In 2014, Southern states accounted for 50% of both new HIV infections and undiagnosed infections. HIV incidence and undiagnosed infection decreased in the United States during 2010–2014; however, outcomes varied by state and region. Progress in national HIV prevention is encouraging but intensified efforts for testing and treatment are needed in the South and states with high percentages of undiagnosed infection.