BCG Vaccine effetive in Reducing TB Risk in Children especially in Low-Incidence Areas: Meta-Analysis

The study led to the following findings:

• A total of 8,242 participants were enrolled across 32 studies.
• The overall protective effectiveness of the BCG vaccine against TB infection was 18%, with a relative risk (RR) of 0.82.
• In low-TB incidence areas, BCG showed a higher effectiveness of 29%, with a relative risk of 0.71.
• In high-TB incidence areas, the effectiveness was not significant, with a relative risk of 0.95.

According to the authors, BCG vaccination offers protective effectiveness against Mycobacterium tuberculosis infection in children, with a notable 29% reduction in infection risk observed in low TB incidence regions. However, the vaccine did not show significant protection in high-incidence settings, prompting the authors to highlight the need for region-specific vaccination strategies and further research to improve TB prevention where the burden is highest.

The authors also acknowledged several limitations of their study, including the exclusion of immunosuppressed children, reliance on scars or medical records for determining vaccination status, and the inclusion of observational cohort studies, which may introduce selection and misclassification biases. Additionally, high heterogeneity in IGRA results remains a concern. They stress the need for future studies to use more consistent and reliable methods, such as electronic health records, to enhance the accuracy and applicability of findings.

Reference:

Cai, S., Luo, Q., Zhou, G., Guo, X., Dong, Y., Chen, H., Luo, S., He, J., Xia, Y., Li, H., Zhou, Y., & Song, C. (2025). Effect of Bacillus Calmette-Guérin vaccination against Mycobacterium tuberculosis infection in children: An updated systematic review and meta-analysis. International Journal of Infectious Diseases, 107909. https://doi.org/10.1016/j.ijid.2025.107909