US guidelines recommend routine HIV screening of all adults and adolescents at least once. The population-level impact of this strategy is unclear and will vary across the country.
We constructed a static linear model to estimate the optimal ages and incremental impact of adding one-time routine HIV screening to risk-based, prenatal, symptom-based, and partner notification testing. Using surveillance data and published studies, we parameterized the model at the national level and for two settings representing subnational variability in the rates and distribution of infection: King County, WA and Philadelphia County, PA. Screening strategies were evaluated in terms of the percent of tests that result in new diagnoses (test positivity), cumulative person-years of undiagnosed infection, and the number of symptomatic HIV/AIDS cases.
While routine HIV screening may contribute meaningfully to increased case detection in persons not captured by targeted testing programs in some settings, this strategy will have a limited impact on population-level outcomes. Our findings highlight the importance of a multipronged testing strategy with continued investment in risk-based screening programs.
Depending on the frequency of risk-based screening, routine screening test positivity was maximized at ages 30-34 years in the national model. The optimal age for routine screening was higher in a setting with a lower proportion of cases among men who have sex with men. Across settings, routine screening resulted in incremental reductions of 3-8% in years of undiagnosed infection and 3-11% in symptomatic cases, compared to reductions of 36-69% and 41-76% attributable to risk-based screening.