Evaluating the potential of HIV self-testing to reduce HIV incidence in EHE districts: a modeling study

Background: High HIV transmission persists in many U.S. jurisdictions despite prevention efforts. HIV self-testing offers a means to overcome barriers associated with routine laboratory-based testing but carries a risk of increasing incidence if replacement effects reduce overall test sensitivity. Methods: A linearized four-compartment HIV transmission model was applied to 38 Ending the HIV Epidemic (EHE) priority jurisdictions. A threshold testing level was defined to counterbalance potential negative effects from reduced self-test sensitivity. Both the percentage of self-tests and the overall testing rate were varied to quantify 10-year changes in HIV incidence. Results: Substantial heterogeneity emerged across districts. Incidence reductions exceeded 5 percent in some areas, while others saw only minor effects. Jurisdictions with higher baseline testing displayed an elevated risk of increased incidence from substitution of laboratory-based testing with self-tests. In contrast, a derived Awareness Reproduction Number, capturing transmissions attributable to undiagnosed infection, strongly correlated with the magnitude of possible incidence declines. Conclusions: Local epidemiological context is pivotal in determining the risks and benefits of HIV self-testing. Jurisdictions with robust testing systems may face a greater likelihood of inadvertently raising incidence, whereas those with a high number of individuals stand to achieve notable transmission reductions. Tailoring self-testing strategies based on jurisdiction-specific conditions can maximize public health benefits while minimizing unintended consequences.