SUMMARY/ABSTRACT Despite the scale-up of free antiretroviral treatment (ART), HIV incidence among men who have sex with men (MSM) in Perú remains high. Delayed diagnosis and suboptimal linkage to care are two important factors driving onward transmission. New strategies to increase rates of testing and promote timely linkage to HIV treatment and prevention are greatly needed. Venue-based testing and mobile health (mHealth) are two promising strategies that could address these challenges by mitigating key barriers to care experienced by MSM in Perú. Based on our previous work, offering HIV testing at social venues (e.g. bars/discos, public plazas) in Lima is acceptable and identifies MSM with previously undiagnosed HIV infection. Extending this to sex-on-premises venues (SOPVs: saunas, sex clubs, hourly hotels) could reach a particularly vulnerable sub-population of MSM, including those not reached by clinic-based testing. One potential pitfall of venue-based HIV testing is low linkage to care among newly diagnosed HIV+ individuals. WelTel is an evidence-based mHealth platform that may be well-suited to assist by adapting its theory-guided two-way messaging approach to support linkage to care – and prevention – among MSM reached for HIV testing at SOPVs. In this proposal we will develop, refine, and conduct feasibility testing of a multi-component HIV testing and linkage-to-services intervention for MSM in Perú, consisting of two core components: 1) SOPV-based HIV testing and 2) “AppSalud”, a novel tailored application of WelTel to facilitate linkage to HIV services. In AIM 1, we will conduct formative research with the target population and key stakeholders to guide development of the intervention. In AIM 2, we will develop AppSalud by reconfiguring WelTel with new tailored content, then beta test it with both potential user types: (a) MSM, and (b) providers at HIV clinics in Lima (to test the provider interface). Guided by the “mCFIR”, a mHealth- specific version of the Consolidated Framework for Implementation Research (CFIR), we will conduct a mixed methods analysis exploring potential implementation barriers and facilitators for AppSalud from the perspectives of both MSM and providers. In AIM 3, we will conduct a feasibility trial of the multi-component intervention (SOPV- based HIV testing plus AppSalud), comparing 3 HIV testing formats: rapid point-of-care testing (POCT), home based self-testing (HBST), and referral for clinic-based testing (RCBT). Supported by a team of experienced international HIV investigators and outstanding institutions in both the U.S. and Perú, these studies constitute the mentored clinical research component of the candidate’s career development plan. In parallel with this research, the candidate will pursue additional training in implementation science, qualitative/mixed methods, mHealth, and intervention trials, guided by a multidisciplinary team of committed mentors with expertise in each of these areas. The tra...