ABSTRACT HIV and TB are leading and linked global epidemics. Household members of people with TB have an elevated prevalence and incidence of both TB and HIV. HIV pre-exposure prophylaxis (PrEP) reduces HIV acquisition by >90%, and both WHO and the Uganda Ministry of Health recommend PrEP as part of a comprehensive prevention package for HIV-negative persons with substantial exposure to HIV. New implementation approaches are needed to ensure that PrEP reaches all people who could benefit. A promising implementation approach to increase PrEP access is through household-based TB contact investigation, which is a leading strategy to decrease TB morbidity and mortality, particularly in high-incidence settings like Uganda. Care models that integrate HIV testing in household TB contact investigation are being evaluated. However, PrEP has not been integrated into TB household contact investigation in high-prevalence settings. Recently, we found that couples identified in households affected by TB in Kampala, Uganda were twice as likely to be serodifferent for HIV than couples in the general population (16% vs. 8%), suggesting that people living in TB-affected households may benefit from PrEP. Multiple studies have shown that household-based linkage to PrEP is feasible and effective in high HIV-burden settings, including among HIV serodifferent couples and pregnant people. We therefore propose to adapt the proven intervention of PrEP to a new setting of household TB contact investigation and evaluate its implementation, effectiveness, and costs using the RE-AIM implementation framework, a widely used framework for evaluating how proven interventions perform in a new delivery context. We hypothesize that integrating HIV prevention into household TB contact investigation will be a feasible, acceptable, effective, and cost-effective strategy for expanding access to status-neutral HIV services, including HIV self-testing and linkage to antiretroviral therapy and PrEP. In Aim 1, we assess the implementation and effectiveness of home-based HIV self-testing and PrEP initiation versus standard clinic referral for PrEP during household TB contact evaluation in Uganda. We use a household-randomized trial design and test the hypothesis that home-based PrEP initiation will increase PrEP uptake and retention compared to clinic referral. In Aim 2, we use qualitative methods to examine the processes of implementing HIV self-testing and PrEP during household TB contact investigation. In Aim 3, we estimate the cost-effectiveness of the strategy to integrate home-based HIV testing and PrEP with household TB contact investigation to assess its sustainability. This work is impactful because understanding how to offer HIV self- testing and PrEP in the setting of household TB contact investigation will facilitate increased use of PrEP, an underutilized innovation for HIV prevention, by leveraging existing health programs.

NARRATIVE HIV and tuberculosis (TB) are two infections that often occur among members of the same household and cause a high number of deaths globally. This study tests an implementation strategy to include HIV testing and medications to prevent HIV infection as part of public health outreach to household members of people with TB in Uganda. We hypothesize that this approach could reduce HIV infections by leveraging existing TB public health programs to also deliver medications to prevent HIV.