Incidence of Bacille Calmette-Guérin associated lymphadenitis in healthy children: A systematic review and meta-analysis.

Few systematic reviews or meta-analyses have addressed on the incidence of Bacille Calmette-Guérin (BCG) lymphadenitis in healthy children. A systematic literature search was independently conducted by two researchers using four English and Korean databases (PubMed, Scopus, KMbase, RISS). The risk of bias was assessed. A total of 52 peer-reviewed journal articles (about 1.8 million children) were included in meta-analyses. The incidence proportion of BCG lymphadenitis ranged from 0.0% to 25.6%. The pooled incidence proportion was 2.5% (95% CI, 1.6-3.6; I2 = 99%). Studies employing active (vs. passive) surveillance reported a significantly higher incidence proportion of lymphadenitis, as did randomized controlled trials (vs. prospective and retrospective cohort studies). Also, the incidence significantly differed according to study quality, publication period, and BCG strain. This study highlights substantial variability in the incidence of BCG lymphadenitis among diverse studies and underscores the influence of surveillance methods, study design, and vaccine strain on reported outcomes.