Tuberculosis transmission among children and adolescents in schools and other congregate settings: a systematic review.

Children, especially those aged <5 years, and adolescents are at increased risk of progression to active TB disease when infected. Management of childhood TB outbreaks is crucial for TB elimination especially in low burden countries. We searched the electronic databases MEDLINE-CINHAL-EMBASE up to July 2017 for primary studies reporting on TB incidents which involved teacher/child-caregiver, relative or students diagnosed with TB in a school/childcare setting or in other congregate settings attended by children and adolescents. Out of 10,481 citations, 74 studies, published mostly in low TB burden countries from 1950 to 2017, describing 128 incident investigations, were included. Overall 5025 (14.2%) LTBI and 811 (2.3%) TB cases were diagnosed among 35,331 screened individuals. Incidents occurred mainly in schools (89.1%) where index cases were more frequently students (63.3%) than teachers/caregivers; almost all of the incidents exposing children aged 2-5 were attributable to a teacher/caregiver index case. In 68 individual contact investigations the pooled proportions of TB and LTBI among those exposed were 0.03 (95%CI 0.02-0.04) and 0.15 (95%CI 0.13- 0.18). The overall risk of developing TB disease in school-congregate settings seems slightly lower than in high-income country household settings. Public health interventions targeting school-congregate settings may be critical to overall TB control and towards TB elimination in low-burden countries.