Modeled transmission risk of Mycobacterium tuberculosis (Mtb) in schools in South Africa, Switzerland, and Tanzania.

Annual transmission risk (median as dots, interquartile range as boxes, and 95%-CrI as lines) of Mtb. Three scenarios are considered: low (70% breathing, 25% speaking, 5% loud speaking), medium (50% breathing, 40% speaking, 10% loud speaking), and high activity (30% breathing, 50% speaking, 20% loud speaking).