ABSTRACT
PURPOSE: The prevalence of atopic diseases has been increasing remarkably. The less frequent opportunities for infection early in life, especially mycobacteria exposure, parallel this higher prevalence of atopic diseases. Bacille Calmette-Gu rin (BCG), a potent inducer of Th1 immune response, has been suggested to suppress Th2 response which is known to mediate IgE-mediated atopic disorders. This study was done to investigate whether there is any relation between the number of BCG scars and the prevalence of atopic disorders in early childhood. METHODS: We surveyed 393 parents with a children who were given percutaneous multi- puncture BCG vaccination within four weeks after birth. The main questions concerned the past history and present illness of physician-diagnosed atopic diseases (atopic dermatitis, bronchial asthma, and allergic rhinitis), the number of BCG scars (range; 0-18), and potential confounders such as gender, parental atopy, maternal smoking and environmental cofactors. The prevalence rate of each atopic disease was measured and analysed according to the number of BCG scars. RESULTS: Each prevalence rate was 18.1% for atopic dermatitis, 9.4% for bronchial asthma, 14.6% for allergic rhinitis, and 32.3% for any of them. All of them had received BCG vaccination during the first four weeks of life. The children with 15 or more BCG scars had a significantly lower prevalence of any atopic disease (22/99, 22.2%) as compared to those with four scars or less (51/125, 40.8%) by simple regression analysis. (P value=0.02) But this association was not significant after controlling for potential confounders. (P value= 0.26) CONCLUSION: This survey demonstrated a weak relation between a larger number of BCG scars and less atopy development at early childhood. But the relation was not so significant. Further studies are needed.