Objectives: BCG vaccination policy is greatly debated. An important issue for countries using the vaccine is to try and estimate any influence it has on the tuberculosis (TB) incidence in their population. The aim of this study is to estimate the effectiveness of the BCG vaccine in infants in Ireland.

Methods: We searched PubMed and Embase for studies assessing a relative reduction in TB events after vaccination in infants. Studies meeting relevant inclusion and exclusion criteria were sought. Observational data from Ireland was combined with raw data from studies identified in the literature in a random-effects meta-analysis model to estimate the relative risk (RR) of vaccine efficacy against pulmonary TB, extra-pulmonary TB (EPTB), TB meningitis and TB deaths.

Results: Two meta-analyses were found. The first metaanalysis reviewed identified 5 randomised control trials and 11 case control studies against pulmonary TB (Trials 0.26 95% CI 0.17, 0.38; Cases 0.48 95% CI 0.37, 0.62) and TB deaths (Trials 0.35 95% CI 0.14, 0.88). The second meta-analysis identified a further 7 case-control studies and evaluated BCG efficacy against EPTB (0.23 95%CI 0.13, 0.42] and TB meningitis (0.27 95%CI 0.21, 0.33). Estimates from observational data from Ireland for pulmonary TB were (0.14, 95%CI 0.09, 0.20), EPTB (0.11, 95%CI 0.05, 0.21), TB meningitis (0.17, 95%CI 0.04, 0.75) and TB deaths (0.13, 95%CI 0.00, 6.37). Pooled RR estimates from Irish data and international estimates show a significant reduction in TB cases: Pulmonary TB: 0.26 (95% CI: 0.13, 0.54), EPTB: 0.16 (95%CI: 0.08, 0.34), TB meningitis: 0.27 (95%CI: 0.21, 0.34) and TB deaths: 0.33 (95%CI: 0.14, 0.81).

Conclusions: This meta-analysis of local observational data with international trial data indicates that vaccination of infants with the BCG vaccine reduces the risk of pulmonary TB, EPTB, TB meningitis and TB deaths.

Value in Health, Volume 16, Issue 7, Page A331

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