Brianna Empringham ^1* Angela Karellis ² Marta Fernandez-Suarez ³ Sergio Carmona ³ Nitika Pai ² Alice Zwerling ¹

• ¹ University of Ottawa, Ottawa, Canada
• ² McGill University, Montreal, Quebec, Canada
• ³ Foundation for Innovative New Diagnostics, Geneva, Geneva, Switzerland

HIV self-testing (HIVST) is an innovative strategy that has been shown to increase uptake of HIV testing compared to conventional facility-based testing. Implementation of HIVST with digital-based supports may help facilitate testing accessibility and linkage to care after a reactive self-test. Economic evidence around community-based implementation of HIVST is growing however economic evidence around digital-based HIVST approaches remains limited. We used previously published cost and efficacy data from HIVST interventions, with the specific intervention modeled varied between scenarios. Digital-based interventions included text messaging campaigns and online websites that promoted uptake and linkage to care of HIVST. Community-based interventions included door-to-door distribution, peer-incentivized distribution, and mobile testing units. Using data from the literature we parameterized a combined Markov and decision analytic model to assess the cost-utility of digital-based HIVST implementation across Malawi, South Africa and Brazil compared to both community-based HIVST and facility-based testing.We found that HIVST was cost-effective compared to facility-based testing in all settings investigated. Our scenarios predicted that digital-based HIVST was associated with a mean incremental cost of $769-$17839 USD/DALY averted compared to facility-based testing across Malawi, South Africa and Brazil. Digital-based HIVST ranged from cost-saving to an incremental cost of $7300/DALY averted compared to community-based HIVST.Main drivers of cost-utility included HIV test and treatment costs, HIV test-positivity, rates of linkage to care and antiretroviral (ART) initiation rates. Digital-based supports were associated with increased cost compared to facility-based testing, but also had increased utility which drove favorable cost-utility estimates.HIVST with digital supports has the potential to be a highly cost-effective approach with potential to make HIV testing more available and accessible, increasing overall uptake and coverage of HIV testing. Digital supports can also support linkage to care, which we have identified as a major driver of cost-utility. Strategies to improve cost-utility include decreasing testing costs, targeting key populations with increased rates of HIV test-positivity and ensuring strong supports for linkage to care.