BCG vaccination and allergy: A systematic review and meta-analysis

• Published in: Journal of allergy and clinical immunology 2011-01, Vol.127 (1), p.246-253.e21
• Main Authors: Arnoldussen, Denise L., BSc, Linehan, Mary, PhD, Sheikh, Aziz, MD
• Format: Article
• Language: English
• Subjects: Allergies; Allergy; Allergy and Immunology; Asthma; atopy; Bacterial diseases; BCG vaccination; BCG Vaccine - therapeutic use; Biological and medical sciences; Child; Clinical trials; Disease; Food allergies; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Hay fever; Human bacterial diseases; Humans; Hypersensitivity - prevention & control; Hypotheses; Immune system; Immunopathology; Infectious diseases; Medical sciences; meta-analysis; Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis; Studies; systematic review; Tuberculosis and atypical mycobacterial infections; Vaccines
• ISSN: 0091-6749; 1097-6825
• DOI: 10.1016/j.jaci.2010.07.039

Background There is conflicting evidence on whether BCG vaccination might represent an effective primary preventative strategy against the development of allergic sensitization and disease. Objectives We sought to systematically review the relationship between BCG vaccination and the risk of sensitization, eczema/atopic dermatitis, allergic rhinoconjunctivitis, asthma, and other allergic conditions, such as food allergy and anaphylaxis. Methods Four international databases were searched for published epidemiologic or interventional studies. Additional online study databases were searched and vaccine manufacturers and a panel of international experts were contacted in an attempt to locate unpublished or ongoing studies. Quality assessment was undertaken by using internationally established criteria. Meta-analyses were undertaken by using fixed- or random-effects modeling. Funnel plots were used to assess for the risk of publication bias. Results We identified 767 articles, of which 17 satisfied our inclusion criteria; there was only 1 randomized controlled trial, with the remaining studies being epidemiologic investigations. Meta-analyses did not show any protective effect of vaccination against the risk of sensitization, as judged by specific IgE tests (odds ratio [OR], 1.31; 95% CI, 1.07-1.60) or skin prick testing (OR, 0.87; 95% CI, 0.67-1.13); the risk of atopic eczema/dermatitis (OR, 0.84; 95% CI, 0.64-1.09); or the risk of allergic rhinoconjunctivitis (OR, 1.07; 95% CI, 0.89-1.28). BCG vaccination was associated with a protective effect against the risk of asthma (OR, 0.73; 95% CI, 0.56-0.95), although this might be explained by publication bias. Conclusions BCG vaccination is unlikely to be associated with protection against the risk of allergic sensitization and disease. The observed possible benefit in relation to the development of asthma is unlikely to be due to allergic sensitization.