The goal of this study is to understand the effects of vitamin D supplementation on immunological outcomes among patients with tuberculosis.

In this randomized trial, the investigators will enroll 200 adults with active pulmonary tuberculosis (TB; among whom 40 have HIV co-infections) at the time of TB diagnosis in S India. The intervention will include daily vitamin D supplementation in 3 treatment arms (600, 2000, and 4000 IU vitamin D), compared to placebo, for 12 months. The investigators' primary objectives are to assess how vitamin D supplementation affects immunity (immunological markers, immune competence) and serum vitamin D levels. Secondary outcomes include TB treatment outcomes (successful sputum smear conversion, relapse) in all patients, and human immunodeficiency virus (HIV) disease progression among a subset of patients with HIV co-infection.

Inclusion Criteria:

• Active TB diagnosis by GeneXpert
• HIV infection status (according to AMC HIV clinic medical records of enzyme-linked immunosorbent assay [ELISA] results)

Exclusion Criteria:

• Children (<18 years of age)
• 60 years of age
• Pregnant at baseline
• Other severe complications or illnesses requiring hospitalization
• Received TB treatment for greater than 4 weeks in the past 5 years
• Refused to participate
• Residing in a geographic location > 1 hour from AMC (by public transit)