OBJECTIVE: Quantify tuberculosis (TB) risk attributable to dorm room exposure in addition to classroom exposure.
METHODS: Adolescent school contact investigations were conducted for every reported index TB case, and similar contact investigations were conducted in selected community-control classes from November 2016 to October 2017 in Guangxi, China.
RESULTS: A total of 6263 contacts of 112 index TB cases and 6130 classmates of 112 controls were investigated. There were 14, 12 and 2 new active TB cases detected among classmates/non-roommates of index cases, classmates/roommates of index cases and control classmates, respectively. Compared with control contacts, the adjusted relative risk (95% confidence interval (CI)) and population attributable fraction (PAF) for being a classmate/non-roommate of the index case increased the risk of active TB diagnosis to 8.44 (95% CI: 1.31-54.48) and 44.1%. The adjusted RR and PAF for being a classmate/roommate of the index case was 29.37 (95% CI: 3.80, 227.11) and 41.4%. Being classmates/roommates significantly increased the risk of TB compared to a classmate/non-roommate of the index case (RR=3.48, 95% CI: 1.64, 7.40).
CONCLUSION: The additional risk of TB due to exposure in the dorm room should be taken into account in planning of TB prevention and control in boarding schools.