The Prevalence of Chest Radiography Abnormalities Suggestive of Inactive Tuberculosis and Their Burden of Tuberculosis Infection Among Rural Residents: A Population-Based Screening Study

Background: Individuals with chest radiography indicating inactive tuberculosis (TB) has been suggested to be one of the high risk populations for developing active TB from latent infection. The burden of this specific population and their TB infection status has been rarely studied in China. Method: We conducted a population-based screening study to investigate the prevalence of inactive TB radiographic abnormalities and their current TB infection status among rural residents. Chest radiography examination and Interferon Gamma Release Assay (IGRA) testing were performed for all eligible rural residents with record of anti-TB treatment. While for participants without recorded previous TB, IGRA testing was conducted only for those with radiographic abnormalities indicating inactive TB (i.e. fibrosis, calcification, nodule, and pleural incrassation). Findings: A total of 46,041 rural residents voluntarily participated in the study. Around two thirds (70·39%, 1,583/2,249) of participants with anti-TB treatment records showed hint of inactive TB lesions, while it was 6·87% (3,008/43,792) for those without treatment history. Among participants with inactive TB lesions, IGRA positivity was 54.15% (855/1,579) and 28·77% (862/2,996) for those with and without anti-TB treatment records, respectively. IGRA positivity was found to be varied with respect to the type of inactive abnormalities. Interpretation: Individuals with inactive TB lesions and their remarkably high prevalence of TB infection should be attached more attention for preventing occurrence of active TB in high burden areas like China. Funding: This work was supported by the National Science and Technology Major Project of China [2017ZX10201302-002], the CAMS Innovation Fund for Medical Sciences [2016-I2M-1-013] and [2019-I2M-2-005]. Declaration of Interests: All co-authors declare that we have no conflicts of interest. Ethics Approval Statement: The ethics committees of the Institute of Pathogen Biology and the Chinese Academy of Medical Sciences approved the study protocol with approval number of IPB-2018-1.