Bacterial immunotherapy in children with wheezing attacks: clinical impact and mechanism of action

Background: Recurrent wheezing affects one third of children being a global health problem with considerable expenditure and impact on quality of life. Virtually all wheezing attacks (WA) in young children are of viral etiology. Their prevention is a major concern as effective therapies are still lacking. Aims: To evaluate the efficacy and safety of a mucosal whole-cell inactivated polybacterial preparation (MV130) in the prevention of WA, and to investigate the underlying mechanism of action. Methods: A randomized, double-blind, placebo-controlled, parallel-group study, including 120 children Results: A reduction of 40% in the number of WA in the active vs the placebo group (p Administration of MV130 conferred protection to intranasal viral infection in mice. This non-specific resistance was mediated by trained immunity. Conclusion: We provide evidence for the first time that a mucosal (sublingual) polybacterial formulation induces trained immunity, confers broad protection beyond the pathogens included in the preparation and shows clinical efficacy against a virus-related condition such as WA, with an excelent safety profile.