Abstract
Background: The objective of the study was to determine whether Bacillus Calmette-Guerin (BCG) vaccination protects against Mycobacterium tuberculosis infection as assessed by interferon gamma release assays (IGRA) in children.
Methods: Systematic review of observational cohort studies conducted as part of investigation of children less than 16 years of age recently exposed to infectious tuberculosis. Risk estimates were combined using random effects meta-analytic models.
Results: The primary analysis included 14 studies and 3855 participants and estimated an overall risk ratio (RR) of 0.81(95% CI = 0.71-0.92), indicating a protective efficacy of 19% against infection among vaccinated children after exposure compared to unvaccinated children. The observed protection was similar when estimated using the two types of IGRA test (ELISpot or QuantiFERON).
Restricting the analysis to the 6 studies (n=1748) with information on progression to active tuberculosis at the time of screening showed protection against infection of 27% (RR 0.73 (0.61-0.87)) compared to 71% (RR 0.29 (0.15-0.58)) against active tuberculosis. Among those infected, protection against progression to disease was 58% (RR = 0.42 (95% CI = 0.23-0.77))
Conclusions: BCG protects against M. tuberculosis infection as well as against progression from infection to disease.
- © 2014 ERS
