Neonatal BCG-vaccination has no effect on recurrent wheeze in the first year of life. A randomized clinical trial

Publication date: Available online 25 March 2017
Source:Journal of Allergy and Clinical Immunology
Author(s): Lisbeth Marianne Thøstesen, Lone Graff Stensballe, Gitte Thybo Pihl, Jesper Kjærgaard, Nina Marie Birk, Thomas Nørrelykke Nissen, Aksel Karl Georg Jensen, Peter Aaby, Annette Wind Olesen, Dorthe Lisbeth Jeppesen, Christine Stabell Benn, Poul-Erik Kofoed
BackgroundRecurrent wheeze is frequent in childhood. Studies have suggested that Bacillus Calmette-Guérin (BCG) vaccination may have non-specific effects, reducing general non-tuberculosis morbidity, including respiratory infections and atopic diseases. The mechanisms behind these non-specific effects of BCG are not fully understood, but a shift from Th2 to Th1-response has been suggested as a possible explanation.ObjectiveWe hypothesized that BCG at birth would reduce the cumulative incidence of recurrent wheeze during the first year of life.MethodsThe Danish Calmette Study is a multicenter randomized trial conducted from 2012-2015 at three Danish hospitals. The 4262 newborns of 4184 included mothers were randomized 1:1 to BCG (SSI strain 1331) or to a no-intervention control group within 7 days of birth; siblings were randomized together as one randomization unit. Exclusion criteria were gestational age <32 weeks, birth weight <1000g, known immunodeficiency, or no Danish-speaking parent. Information was collected through telephone interviews and clinical examinations at 3 and 13 months of age; the data collectors were blinded to randomization group.Recurrent wheeze was defined in several ways, the main definition being: "physician-diagnosed and medically treated recurrent wheeze up to 13 months of age".ResultsBy 13 months 211/2100 (10.0%) children in the BCG group and 195/2071 (9.4%) children in the control group had been diagnosed by a medical doctor with recurrent wheeze and received anti-asthmatic treatment (relative risk 1.07 (95% confidence intervals 0.89-1.28)). Supplementary analyses were made, including an analysis of baseline risk factors for developing RW.ConclusionNeonatal BCG had no effect on the development of recurrent wheeze before 13 months of age.

Teaser

Neonatal BCG vaccination cannot be used prophylactically against recurrent wheeze in Denmark, but if a BCG vaccination is necessary for other reasons, the infant can be BCG vaccinated without concerns of recurrent wheeze.


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