Screening of Close Contacts of Pulmonary Tuberculosis in an Urban Area in Shanghai, China: a Cross-Sectional Study

Abstract Objectives : The study aimed to explore the risk factors of close contacts developing pulmonary tuberculosis (TB) and evaluate the socioeconomic benefits of TB prevention and control expenditure in Putuo District, Shanghai. Study design : A cross-sectional study was conducted among close contacts of pulmonary TB patients in Putuo District from 2017 to 2018. Methods : A symptom questionnaire, chest X-ray (CXR) and interferon-gamma release assay (IGRA) were carried out to screen the consenting close contacts. Three sputum smears and cultures were collected from close contacts whose screening was positive. Results : A total of 1036 individuals were included in this study, with an average age of 47.3±19.4 years old, including 427 males and 609 females. Four of the close contacts had suspected TB symptoms. Fourteen had abnormal CXR with suspected TB and 52 had positive IGRA results. Multivariate analysis showed that index cases with positive sputum smears, close contacts with suspected TB symptoms and their interaction term were at significantly higher risk of developing TB. A total of $67,372.6 was invested. Eight active TB cases were screened and successfully treated in this study, saving $88,083.11 by avoiding new cases by conducting close contact screening in this study and $1,203,953.05 in the socioeconomic value. Each dollar generated $19.18 in socioeconomic benefits. Conclusions : A comprehensive package, involving funding and introducing new techniques needs to be developed to further optimize the screening strategies of close contacts, particular emphasis should be placed on those with bacteria-positive index cases or those with suspected TB symptoms during follow-up.