Abstract We propose to evaluate the impact, implementation and cost effectiveness of VITAL Start, a brief facility- based video intervention for HIV-positive (HIV+) pregnant women, in a multisite randomized controlled trial (RCT) in Malawi with the primary composite outcome of retention and adherence (viral suppression) 12 months after starting antiretroviral therapy (ART). Universal HIV testing and treatment can accelerate population-level ART initiation and is critical to realize the UNAIDS 90-90-90 goals. Malawi pioneered Option B+ (B+), a novel application of test-and-treat that provided life-long ART for HIV+ pregnant and breastfeeding women. While maternal ART uptake improved 7-fold, retention and adherence remained suboptimal: only 59% were retained after two years, and of these, only two-thirds achieved adequate ART adherence. Other B+ countries are observing steep drops in retention. Reasons are multi-factorial; women who feel healthy are unprepared to commit to lifelong ART; inadequate counseling due to increased demands on healthcare workers; and limited partner disclosure affecting retention and adherence. There is an urgent need for evidence-based interventions to improve retention and adherence that can be easily incorporated into overextended health systems. Using formative participatory research, applied theoretical frameworks, and evidence-based message framing techniques, we created an innovative 37-minute video-based intervention for pregnant women newly initiating ART. The video promotes retention and adherence by providing a VITAL Start (Video intervention to Inspire Treatment Adherence for Life) at the critical teachable moment before committing to lifelong ART. Preliminary findings suggest high levels of patient and HCW satisfaction, and improved ART knowledge, rates of partner disclosure, and retention. With these promising results, the proposed study aims to rigorously evaluate the impact, implementation, and cost-effectiveness of VITAL Start. A sample of 796 HIV+ pregnant women will be randomized on a 1:1 basis to receive VITAL Start or standard of care counseling prior to ART initiation. The primary endpoint will be a composite of retention and adherence (virologic suppression), at 12 months post ART initiation. Secondary outcomes include self-reported adherence, pharmacy data, and tenofovir diphosphate testing. We will also examine the delivery of VITAL Start via surveys and interviews with patients, partners, and HCW and conduct cost-effectiveness analyses. If successful, VITAL Start will provide an intervention that (1) standardizes and improves counseling at a critical teaching moment through an engaging and culturally sensitive experience, (2) is inexpensive and rapidly scalable without decelerating ART expansion, and (3) allows more efficient use of precious HCW time. Building on a longstanding collaboration with the Malawi Ministry of Health, we are poised to support rapid dissemination of VITAL Start if the re...