PROJECT SUMMARY India has the third-highest number of persons with HIV. One-quarter of deaths among persons with HIV are due to TB. Undernutrition is the leading risk factor for TB in India. TB transmission from HIV-negative persons likely fuels the TB epidemic among Indian persons with HIV. I hypothesize that population-scale nutritional interventions would reduce TB incidence and mortality among persons with and without HIV. I also hypothesize that, in an Indian context, in-kind nutritional supplementation would be more cost-effective than cash transfers. Models allow us to generate representations of real-world problems in mathematical language which can be used to gain insights and to make projections. The proposed Nutritional Interventions to End Tuberculosis among persons with HIV in India (NUTRIENT-India) study will have the following aims: 1. Quantify the long-term impact of population-scale nutritional interventions on TB incidence and mortality among persons with and without HIV in the Indian state of Tamil Nadu using a microsimulation model 2. Estimate the impact and cost-effectiveness of a variety of nutritional interventions to decrease TB incidence & mortality among persons with and without HIV For aim 1, we will develop the microsimulation model and validate it. We will then calibrate the model using data from national health surveys and primary data from the ongoing TB Learning the Impact of Nutrition (LION) study of nutritional interventions. For aim 2, we will synthesize evidence on the impact of cash transfers and in-kind transfers on nutritional status of recipients. Next, we will adapt an existing Markov model to simulate three different nutritional interventions: 1) 2600 Kilocalories (Kcal)/d of food, 750 Kcal/d of food, and Rs 500/month cash transfer. We will obtain cost estimates from the TB-LION study and NTEP programmatic costs. After calibrating the model using data from TB-LION and the Regional Prospective Observational Research on Tuberculosis (RePORT)- India consortium, we will conduct cost-effectiveness analysis of the three different nutritional interventions. The NUTRIENT-India study will help quantify the long-term impact of nutritional interventions on TB incidence and mortality among persons with and without TB in India, The study will also define the most cost- effective nutritional interventions in the Indian context. Thus, it will inform policymakers on why they must address this critical TB risk factor that keeps TB entrenched in India and how they can intervene while making maximal use of available resources.