Effect of a Multi-strain Probiotic Formulation on Immune Response to Influenza Vaccination

Randomized clinical trial to determine whether a probiotic formulation containing 4 probiotic strains which belong to Lactiplantibacillus plantarum and Pediococcus acidilactici species can boost the immune response to influenza vaccination evaluated at 4 weeks in a population between 50 and 80 years of age. Secondary outcomes comprise evaluation of immune response at 8 weeks after vaccination, percentage of patients with seroconversion, incidence and duration of influenza-like infections and respiratory infections throughout a 4-month period and safety.