BackgroundOf new HIV infections in the US, 20% occur among young men who have sex with men (YMSM, ages 13-24), but >50% of YMSM with HIV are unaware of their status. Using Adolescent Medicine Trials Network for HIV/AIDS Interventions (ATN) data, we projected the clinical benefit and cost-effectiveness of frequent HIV screening among high-risk YMSM from age 15.MethodsUsing a mathematical simulation, we examined 3 screening strategies: Yearly, 6-monthly, and 3-monthly, each in addition to the Status quo (SQ, 0.7-10.3% screened/year, stratified by age). We used published data (YMSM-specific when available) including: HIV incidences (0.91-6.41/100PY); screen acceptance (80%), linkage-to-care/antiretroviral therapy (ART) initiation (76%), HIV transmission (0.3-86.1/100PY, by HIV RNA), monthly ART costs (2290−3780), and HIV per-screen costs (38).ProjectedoutcomesincludedCD4countatdiagnosis,primaryHIVtransmissionsfromages15−30,quality−adjustedlifeexpectancy,costs,andincrementalcost−effectivenessratios(ICERs,/quality-adjusted life-year saved [QALY]; threshold ≤100000/QALY).ResultsComparedtoSQ,allstrategiesincreasedprojectedCD4atdiagnosis(296to477−515cells/µL)andquality−adjustedlifeexpectancyfromage15(44.4to48.3−48.7years)amongYMSMacquiringHIV.ComparedtoSQ,allstrategiesincreaseddiscountedlifetimecostfortheentirepopulation(170 800 to 178100−185 000/person). Screening 3-monthly was cost-effective (ICER: 4500/QALY)comparedtoSQandreducedprimarytransmissionsthroughage30by40100 000/QALY (ICER: $70 900/QALY).ConclusionsFor high-risk YMSM in the US, HIV screening 3-monthly compared to less frequent screening will improve clinical outcomes and be cost-effective