PROJECT SUMMARY/ABSTRACT This project will assess whether a digital crowdsourced intervention can reduce HIV stigma and promote HIV self-testing among adolescents and young adults (AYA). Globally AYA are at increased risk for HIV acquisition. In Eastern Europe and Central Asia (EECA), new HIV infections among 15-24 year old AYA are expected to increase 28% by 2030. In Kazakhstan, one in four HIV infections occur among AYA. Despite the growing HIV burden among AYA in Kazakhstan, this population has some of the lowest HIV testing rates in the country, largely due to stigma. Yet few efforts in Kazakhstan address HIV stigma and the role it plays as a barrier to HIV testing. Digital technologies and crowdsourcing campaigns (i.e., engaging groups of AYA online to address public health challenges and share solutions) are scalable, cost-effective tools that can increase HIV testing services and reduce HIV stigma in low and middle income countries (LMICs) and other resource-constrained settings. Crowdsourcing may be particularly successful among AYA, given their high levels of social media use and technological literacy. Complementing the crowdsourcing approach, mailing HIV rapid test kits can enable AYA to avoid the stigma associated with attending the AIDS Center and overcome transportation barriers. Study aims are: 1) use a community-based participatory approach that engages local AYA and youth organizations to develop a crowdsourced digital HIV stigma reduction and self-testing intervention to reduce HIV stigma and increase HIV testing among AYA in Kazakhstan; and 2) to pilot test this crowdsourced HIV stigma reduction and self-testing intervention in a preliminary efficacy trial to assess feasibility and acceptability and obtain preliminary estimates of its effects on decreasing HIV stigma (primary outcome) and increasing HIV testing (secondary outcome) among AYA (n=168) in Kazakhstan who received the intervention compared to individuals who did not. This work will result in an integrated digital crowdsourced stigma reduction and self- testing intervention to reduce HIV stigma and improve HIV testing uptake among the key population of AYA in Kazakhstan. Such an intervention addressing HIV stigma and reducing barriers to HIV testing for AYA could increase HIV testing uptake among this population in LMICs and domestically.