Chlamydia trachomatis (Ct) is the most common reportable sexually transmitted infection in the United States that causes severe and costly morbidity. Black youth are disproportionately impacted, with Ct rates 7.5 times higher than the rates among non-Black youth. In over two decades of Ct screening in young women, population-based rates of Ct have declined for White youth but not for Black youth, and clinic-based Ct screening is accessed less frequently than recommended by Black women, indicating that a different approach is needed, particularly when considering structural racism and medical mistrust. We posit that a community- based, seek, test, and treat approach is required. Check It (NICHD/NIAID R01HD086794) was a seek, test, and treat bundled network approach to reducing chlamydia disparities that was designed for young Black men. In 33.5 months of recruitment, we screened 1907 men and found a 10.6% Ct positivity rate. We found that screening men reduced the rate in women by an average of 2.1 percentage points compared to synthetic control sites; for every 5 men screened, 1 infection in women was averted; and that the program costs were $5,468 per QALY gained. The study goal is to further adapt and refine Check It, a seek, test, and treat community-based Ct prevention program aimed to reduce disparities among Black youth in the United States. We will achieve this in three aims: Aim 1. To adapt and refine Check It – Using the ADAPT-ITT framework47 and in collaboration with our intended population, content experts, and community partners, we will make five adaptations to the program: inclusion of women, use of doxycycline, addition of a home collection option, refinement of incentivized peer referral, and extragenital self-collection in the first year and then readapt as needed in the third year. We will conduct interrupted time series analysis & hypothesize that these adaptations will increase enrollment. Aim 2. To determine efficacy and cost-effectiveness of the adapted Check it– After adaptations and implementation among Black youth in New Orleans (N=2322), using Medicaid data, we will compare New Orleans (intervention) to synthetic controls to examine the adapted program's impact on women's Ct rates.48 We will also use time-motion analysis to examine the cost- effectiveness,34 hypothesizing that inclusion of both men and women is cost effective and will logarithmically reduce the rates of Ct infection in women. Aim 3. To examine the feasibility/utility of Ct/GC extragenital and syphilis/HIV testing – Participants will be offered extragenital specimen self-collection & syphilis/HIV testing. We hypothesize that >80% will accept to do extragenital testing and that syphilis/HIV rates will exceed the national average. To break down health disparities, it is essential to go to the communities of those impacted. If successful, Check It II can serve as a model for other sites ultimately reducing Ct disparities on a broader basis. Check It II could...