Investigation of a large school-based outbreak of tuberculosis infection in Eastern China

Background School-based tuberculosis (TB) happens frequently in Eastern China. This study aims to identify the risk factors of a school-based TB outbreak in Eastern China and actions that could be taken to prevent future similar school TB outbreaks. Methods A retrospective cohort study was conducted to quantify the risk of developing TB, while a retrospective review was conducted to identify the contributing factors of the outbreak. Results A total of 411 students were in the same school year as the index case; 25 students with TB were detected. The index case was a 19 year-old male student diagnosed with cavitary smear-positive TB 40 days after complaining of TB symptoms. Being in the same class as the index case resulted in a significantly higher risk of having active TB (OR = 35.2, 95% CI = 11.7–105.9). Contacts with the same sex as index case were at a 3.5-times higher risk of having TB than were female contacts. Participants with a Mantoux testing result ≥10 mm induration were at a 7.2-times higher risk of having TB than those with testing result <10 mm. Conclusions TB contacts with the same sex as index case had a higher risk of having TB. Delayed diagnosis, lack of preventive treatment, and no follow-ups were the typical contributing factors of the outbreak. The capacity of the health authorities should be enhanced to guarantee a proper response to school-based TB outbreaks in Eastern China.