A new study published in the Journal of Translational Medicine was planned to further contribute to the evaluation of the role played by OM-85 – a lysate of 21 common bacterial respiratory pathogens, in the prevention of recurrent respiratory tract infections (RTIs) in children. In this randomized, placebo-controlled, double-blinded, single-center, phase IV trial, 288 children aged 1-6 years were selected from Italy and divided in the ratio 3:3:1. The study assessed the efficacy of OM-85 in reducing the number of new RTI episodes in children with a history of recurrent RTIs and to compare the efficacy of the standard 3-month regimen with that of administration of OM-85 for 6 months during a 6-month study period. The results revealed that the number of RTIs and of children who experienced at least one RTI were significantly lower among patients receiving OM-85 for 3 months than among those who were given placebo. Differences were statistically significant for upper RTIs like common cold/viral pharyngitis and acute otitis media. Days of absence from day-care for children and working days lost by parents were significantly lower in the group with children treated with OM-85 for 3 months, than in the placebo group. However, no difference was found between children who received OM-85 for 3 months and those who received OM-85 for 6 months. In addition, neither the prevalence of atopy nor the history of recurrent wheezing and age of the study child, influenced the results. In fact, benefit was maximally evident among children with a history of frequent recurrences. Furthermore, OM-85 was well tolerated and safe, even in children who received an influenza vaccination. In inference, it was stated that the use of OM-85 for 3 months, in 3 series of 10 consecutive days each time, reduces the risk of recurrent RTIs in children, with a favorable safety profile. The greater effect observed in children prone to several respiratory episodes than in non-prone children suggested that this lysate should be administered, particularly to children with a proven high susceptibility to RTIs.