This is a randomised placebo-controlled trial including 500 otherwise healthy moderate-late preterm infants. Participants will receive bacterial lysate (Broncho-Vaxom, 3,5mg) or placebo powder for ten days each month, from 6 weeks after birth until 12 moths of age. Clinical data will be continuously collected by e-Health and 3 (possibly digital) study visits; with optional biological sampling and lung function at baseline, 6 and 12 months. Main study parameters are doctor diagnosed lower RTI and wheezing episodes in the first year of life. Biological sampling will allow investigation of immune maturation, as well as microbiome development in the respiratory tract and gut. Also, biomarkers for risk-group selection and/or treatment success will be examined.
The primary objective of this study is to reduce respiratory tract infections and wheezing in moderate-late preterms in the first year of life by bacterial lysate administration. Next to determine the correlation of biological markers with respiratory symptoms, immune protection and treatment effect.