Research AppraisalSystematic Review

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

Human vaccines & immunotherapeuticsChoi, BongKyoo, Cho, Hyunjeong, Lee, Ju-Yeun et al.1 Dec 2026DOI

Clinical Snapshot

65CEBM

Evidence: ModerateSystematic Review

PICO Framework

P — Population	Healthy children receiving BCG vaccination
I — Intervention	BCG vaccination
C — Comparator	Not applicable (incidence study)
O — Outcomes	Incidence proportion of BCG-associated lymphadenitis

Bottom Line

This meta-analysis of 52 studies involving 1.8 million children found a pooled BCG lymphadenitis incidence of 2.5% (95% CI: 1.6-3.6%). However, the extremely high heterogeneity (I² = 99%) and wide variation in reported rates (0.0% to 25.6%) significantly limit the clinical utility of this pooled estimate. The incidence varied substantially based on surveillance methods (active vs passive), study design, BCG strain, and study quality. While the large sample size provides statistical power, the marked heterogeneity suggests that local factors, surveillance intensity, and vaccine strain characteristics may be more important determinants of lymphadenitis risk than the overall pooled estimate. Clinicians should interpret these findings cautiously, recognising that actual incidence rates may vary considerably based on local vaccination practices and surveillance systems. The study highlights the need for standardised surveillance methods and reporting criteria for BCG adverse events.

Evidence: Moderate

Key Findings

P Value: Not reported in abstract
Effect Size: 2.5% pooled incidence proportion
Primary Outcome: Incidence proportion of BCG-associated lymphadenitis
Nnt Or Sensitivity: 1 in 40 children (2.5%) develop BCG lymphadenitis
Confidence Interval: 95% CI: 1.6-3.6%

Clinical Application

Results applicable to clinical practice but high heterogeneity limits precise risk estimation Limited relevance as Australia discontinued routine BCG vaccination in most states, though may apply to high-risk populations still receiving BCG Healthy children receiving BCG vaccination, particularly relevant for countries with routine BCG programs

Abstract

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.

References

1.Choi, B., Cho, H., Lee, J. Y., Jeong, J., Ryu, S., Lee, E. K., Lee, J., & Koh, S. (2026). Incidence of Bacille Calmette-Guérin associated lymphadenitis in healthy children: A systematic review and meta-analysis. Human Vaccines & Immunotherapeutics. https://doi.org/10.1080/21645515.2026.2662756

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