BCG Immunization at Birth and Atopic Diseases in a Homogeneous Population of Spanish Schoolchildren

Abstract

Background: The role of immunization with bacillus Calmette-Guérin (BCG) in the prevalence of asthma, hay fever and atopic dermatitis is not definitely established and seems to be influenced by ethnic background. The aim of this study was to analyze the relationship between this immunization and the prevalence of those diseases in a homogeneous population of Spanish schoolchildren. Methods: The International Study of Asthma and Allergies in Childhood (ISAAC) core and environmental questionnaires were used in four different centers of the Spanish North Atlantic coast. Bilbao, San Sebastián and Asturias have a universal BCG immunization policy during the first days of life, whereas La Coruña discontinued this practice in 1989. Except for this center, immunization coverage was above 90%. A random sample of schools of Asturias or all schools in the city district (rest of centers) with children 6 and 7 years old was surveyed. Results: The participation rate was above 70%. After excluding those children born outside Spain, the numbers were 6,762 immunized and 2,828 nonimmunized. After adjusting for gender, age, smoking habits of the father and mother, truck traffic near the household, older and younger siblings and having a cat or a dog during the first year of the child’s life, the adjusted ORs of the BCG-immunized children suffering from asthma, hay fever and atopic dermatitis were respectively 0.87 (95% CI 0.76–1.00), 0.87 (0.75–1.01) and 0.89 (0.76–1.05). Conclusions: BCG immunization offers a weak but significant protection against asthma and hay fever in Spanish schoolchildren.

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

“…17 The main features of the 17 included studies are detailed in Table I. [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] Of particular note was that there was only 1 RCT 32 ; the remaining 16 studies used either cohort (n 5 7, 6 of which were retrospective and only 1 of which was prospective), 17,18,[22][23][24][26][27] case-control (n 5 2) 20,30 or cross-sectional (n 5 7) designs. 19,21,25,28,31,33 Sensitization to common allergens Ten studies investigated the relationship between BCG vaccination and allergic sensitization.…”

“…18,19,[21][22][23][24][27][28][29]32 Analysis showed an overall OR of 0.84 (95% CI, 0.64-1.09) in the risk of eczema/atopic dermatitis (Fig 4); there was significant heterogeneity (I 2 5 89%). The funnel plot was suggestive of publication bias (see Fig E5 in Subgroup analysis was conducted to investigate the source of heterogeneity; analysis of children judged to be at high risk of allergic disorders found a similar effect size (OR, 0.81; 95% CI, 0.64-1.03; see Fig E7, A, in this article's Online Repository at www.jacionline.org).…”

“…jacionline.org). 18,19,[21][22][23][24][26][27][28][29][30][31][32] Because studies often used a range of asthma-related outcome measures, we used the most important reported outcome for metaanalysis. Our preferred order of importance was as follows: lifetime asthma, 12-month prevalence of asthma, lifetime wheezing, and 12-month prevalence of wheezing.…”

Toll-like receptor ligands and atopy: A coin with at least two sides

“…62,63 Moreover, BCG vaccination has been associated with a reduced allergic risk in some, but not all, human clinical trials. [64][65][66] In other investigations heat-killed Listeria species was found to be a potent adjuvant for the induction of T H 1-biased and the inhibition of T H 2-biased responses in mice and dogs. 67,68 Furthermore, rectal vaccination with heatkilled E coli expressing peanut allergen has been reported to reverse allergen-specific hypersensitivities in T H 2-sensitized mice.…”

Allergic Rhinitis and its Impact on Asthma (ARIA) 2008*

“…In developed countries, many studies found an absence of any relationship between BCG vaccination and atopic diseases in children (1011-1017) and young adults (1008). In other developing countries, there was a weak protective effect of BCG vaccination against asthma and hay fever (1018)(1019)(1020). In developing countries, an early BCG vaccination was associated with a weak prevention of atopic diseases (1009).…”