Abstract
In otherwise healthy infants and young children, respiratory tract infections (RTIs) are extremely common. Clinical data have shown that OM-85 could prevent respiratory recurrences in children. However, further studies are needed to explore the true importance of OM-85 in clinical practice. In addition, an unsolved problem is the efficacy of OM-85 when it is administered for two consecutive years. Moreover, another open question is the safety of OM-85 when co-administered with the influenza vaccine. In order to solve these unanswered issues, 200 children aged three to six years with a history of recurrent RTIs, defined as at least six documented episodes of acute RTI in a single year, who had received OM-85 (Broncho-Vaxom(®); OM Pharma, a Vifor Pharma Group Company, Geneva, Switzerland) for two consecutive years (3.5 mg once a day for 10 days for 3 months of each year) were selected and matched based on age, sex, and period of evaluation with children with recurrent RTIs who did not receive OM-85. In the group of children treated with OM-85, the number of patients who did not experience any new episode of RTI, as well as the number of RTIs, wheezing episodes, medical visits, and prescribed antibiotic courses, were significantly lower than that in the group not treated with OM-85. The results were similar in the first and second year of OM-85 administration. A minority of patients showed mild adverse events, and the safety profile was overall good, including in the 49 children who received the influenza vaccination within one month from the beginning of the first cycle of OM-85. Our data suggest that OM-85 can effectively and safely reduce the risk of new infective episodes in children with recurrent RTIs and that a second yearly course of lysate administration can be useful to maintain protection, particularly when the diagnosis of recurrent RTIs is made in younger children for whom it is likely that definitive maturation of the immune system still requires a long time.