Is the prevalence of wheeze in children altered by neonatal BCG vaccination?

BackgroundThe prevalence of asthma and atopic disease has increased in recent decades, but precise reasons for this increase are unknown. BCG vaccination is thought to be among a group of vaccines capable of manipulating the immune system toward TH1 dominance and therefore reducing the likelihood of atopic disease.ObjectiveThe aim of this study was to determine the influence of neonatal BCG vaccination on the prevalence of wheeze in a large community population of children.MethodIn a historical cohort study, a parent-completed questionnaire was used to identify the prevalence of wheeze in BCG-vaccinated and nonvaccinated children in Manchester, England.ResultsThere were 2414 participants aged between 6 and 11 years. In a univariate analysis neonatal BCG vaccination was associated with a significantly lower prevalence of wheeze (odds ratio, 0.69; 95% CI, 0.55-0.86), and statistical significance was retained when the analysis was adjusted for potential confounders (odds ratio, 0.68; 95% CI, 0.53-0.87).ConclusionThese results demonstrate an association between asthma symptom prevalence and neonatal BCG vaccination, relating to a possible 27% reduction in prevalence, and are therefore of considerable public health importance.Clinical implicationsThe capacity of neonatal BCG vaccination to reduce the prevalence of respiratory symptoms in children warrants further investigation.