OM-85 in Paediatric Recurrent Respiratory Tract Infections With Wheezing Lower Respiratory Illness

Inclusion Criteria: * Children of either gender aged between 6 months and 5 years, at Baseline/Randomisation (Visit 2) inclusive. * For children ≥1 year of age, ≥4 RTIs (as reported by parents or LAR of subject), including ≥2 episodes of wLRIs (including ≥1 triggering hospitalisation or medical visit) within 12 months prior to enrolment. OR * For children \<1 year of age, ≥2 RTIs (as reported by parents or LAR of subject), including ≥1 episode of wLRIs (including ≥1 triggering hospitalisation or medical visit) within 6 months prior to enrolment. * Parents or LAR of subject have provided the appropriate written informed consent. Written informed consent must be provided before any study-specific procedures are performed including screening procedures. Exclusion Criteria: * Anatomic alterations of the respiratory tract. * Other chronic respiratory diseases (e.g., tuberculosis, cystic fibrosis). * Any autoimmune disease. * HIV infection or any type of congenital or iatrogenic immune deficiency (including IgA deficiency). * Known severe congenital heart disease. * Haematologic diseases. * Liver or kidney failure. * New-borns before 34 weeks of gestational age. * Malnutrition as per World Health Organization (WHO) definition. * Any known neoplasia or malignancy. * Treatment with the following medications: 1. Injection or oral administration of steroids within 4 weeks prior to study enrolment. 2. Previous and/or concomitant immunosuppressants, immunostimulants, or gamma globulins within 6 months prior to study enrolment. * Previous use within last 6 months of enrolment or ongoing use of bacterial lysates. * Any major surgery within the last 3 months prior to study enrolment. * Known allergy or previous intolerance to investigational medicinal products (IMP). * Any other clinical conditions, that in the opinion of the Investigator, would not allow safe completion of the clinical study. * Other household members have previously been randomised in this clinical study. * Subjects' families expected to relocate out of study area within 24 months of the initiation of the study. * Currently enrolled in or has completed any other investigational device or drug study or receiving other investigational agent(s) within \<30 days prior to screening. * Parents or legally acceptable representative (LAR) who do not have access to internet connection. * Wheezing documented to be caused by gastroesophageal reflux.