The role of nutritional support with probiotics in outpatients with symptomatic acute respiratory tract infections: a multicenter, randomized, double-blind, placebo-controlled dietary study.

Background: A number of laboratory data and clinical studies have shown that probiotic bacteria may be beneficial in respiratory viral diseases. We investigated the role of probiotics in coronavirus disease-19 (COVID -19), post-disease symptoms, and humoral immune responses to viral antigens.

Methods: This was a randomized, double-blind, placebo-controlled, prospective, multicenter study.