Lower prevalence of reported asthma in adolescents with symptoms of rhinitis that received neonatal BCG.
BACKGROUND
BCG is a vaccine used against tuberculosis and leprosy and is an immunostimulant that primes T(H)1 lymphocytes to produce cytokines that antagonize atopy both in animal models and in man. Considering that atopy is the main risk factor for asthma, one can hypothesize that vaccination inducing T(H)1 responses, such as BCG, can be protective against asthma.


METHODS



OBJECTIVE
To estimate the association between neonatal BCG vaccination and prevalence of asthma among adolescents.


METHODS
Cross-sectional study with schoolchildren aged 12-16 years. The presence of a scar compatible with BCG was used as a surrogate of neonatal vaccination. A self administered structured questionnaire was prepared based on that used by the International Study of Asthma and Allergies in Childhood. The prevalence of asthma was categorized according to the report of lifetime wheeze, lifetime asthma, lifetime asthma among those referring allergy and among those referring allergy and sneezing.


RESULTS
Neonatal BCG vaccination was not associated with the overall prevalence of reported wheezing or asthma. However, in the subgroup reporting current allergy and sneezing, neonatal BCG was associated with a 37% reduction of prevalence of lifetime asthma.


CONCLUSIONS
In the population we surveyed, neonatal BCG scar was associated with a reduction in the risk of asthma only in individuals with a past history suggestive of allergic rhinitis.
da Cunha
S S
SS
Infectious Disease Epidemiology Unit, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
Cruz
A A
AA
Dourado
I
I
Barreto
M L
ML
Ferreira
L D A
LD
Rodrigues
L C
LC
D000293:Adolescent; D001249:Asthma / Q000453:epidemiology / Q000517:prevention & control*; D001500:BCG Vaccine / Q000276:immunology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D015995:Prevalence; D012135:Respiratory Sounds; D012221:Rhinitis, Allergic, Perennial / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology*; D014611:Vaccination
D001500:BCG Vaccine