Incidence of infectious diseases in children with Mycobacterium tuberculosis in Japan

Background: In Japan, the universal Bacillus Calmette-Gu&eacuterin (BCG) immunization program for infants aged < 13 months remains in effect. Since 2005, the BCG vaccination history has been required to be reported, in addition to the clinical and treatment status of childhood tuberculosis (TB), through a notification system and made available as epidemiological data. Methods: To understand the epidemiology of childhood TB in Japan under the 2013 Bacillus BCG immunization program modification in Japan, we performed descriptive analysis on the national surveillance data. Results: The median percentage of annual vaccination coverage for infants aged <13 months was 97.0% during the observed period (2007-2022). The age at which the majority of infants received their vaccinations was 3 months before 2013 and 5 months since 2013.During the follow-up period, the number of childhood TB notifications and annual incidence decreased by approximately 60% and 40%, respectively. The analysis revealed correlation between childhood TB and both age and BCG vaccination history, while the impact of the 2013 BCG immunization program modification was not statistically significant. Conclusion: These findings, derived from the national surveillance data in Japan, serve as a valuable resource for future research, offering insights into the efficacy of BCG and the impact of BCG policies.