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Bacille Calmette Guerin Vaccination in Early Childhood and Risk of Allergic Disease: A Systematic Review and Meta-analysis of data from 13 large scale studies
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  • Keyu Zhao,
  • Phoebe Miles,
  • Richard Hubbard,
  • Qiongyan Zhou,
  • Wei Lin,
  • Chao Cao,
  • Suling Xu
Keyu Zhao
Ningbo University Medical School
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Phoebe Miles
Humanities and Social Science,University of Nottingham
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Richard Hubbard
University of Nottingham Division of Epidemiology and Public Health
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Qiongyan Zhou
Department of dermatology, The Affiliated Hospital of Medical School, Ningbo University
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Wei Lin
Department of dermatology, The Affiliated Hospital of Medical School, Ningbo University
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Chao Cao
Ningbo City First Hospital
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Suling Xu
Department of dermatology, The Affiliated Hospital of Medical School, Ningbo University
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Abstract

Background and objectives Several large scale cohort studies suggest that BCG vaccination in early childhood may reduce the risk of allergic disease, but the consequences remain controversial. The objective of this study was to investigate the associations between early childhood BCG vaccination and the risk of developing allergic disease. Methods Eligible studies published on PubMed, EMBASE and Cochrane Central Register of Controlled Trials were systematically sourced from inception to April 2020. Large-scale cohort or cross-sectional studies with 100 participants or more, focusing on the association between BCG vaccine and allergic disease including eczema, asthma and, rhinitis were included. An assessment was undertaken by two independent investigators looking at methods, interventions, outcomes, and study quality. Odds Ratio (OR) with 95% confidence interval (CI) were calculated. Results Our study included 13 large-scale studies involving a total of 260,029 participants. Our quantitative analysis found that administering BCG vaccine in early childhood significantly reduced the risk of developing asthma (OR 0.74, 95%CI 0.61 to 0.91), but there was no association between early childhood BCG vaccination and the risk of developing eczema (OR 0.87, 95%CI 0.68 to 1.11) or rhinitis. (OR 1.03, 95%CI 0.87 to 1.22). The effect of BCG vaccination with asthma was evident especially in European countries (OR 0.59, 95%CI 0.40 to 0.88) and American countries (OR 0.90, 95%CI 0.82 to 0.98) Conclusions Use of BCG vaccination in early childhood may be associated with a reduced risk of allergic disease, especially in European and American countries.