Effect of Bifidobacterium animalis spp. lactis Bl-04 on Rhinovirus-Induced Colds: A Randomized, Placebo-Controlled, Single-Center, Phase II Trial in Healthy Volunteers

Background This study was designed to assess the efficacy of Bifidobacterium animalis ssp. lactis (Bl-04) for prevention of rhinovirus colds and to explore the interactions between the probiotic, the viral infection, the host response and the host microbiome. Methods The effect of ingestion of the probiotic Bl-04 was evaluated in a randomized, double-blinded rhinovirus (RV) challenge study. Healthy volunteers recruited from a university community in USA were randomized 1:1 using a computer generated code to ingest either Bl-04 (n=165) or placebo (n=169) for 28 days and were then challenged with RV-A39, and followed for 14 days. All study interactions and sample collection occurred in dedicated dinical research space. The primary analysis was the effect of the probiotic on the incidence of RV-associated illness. (Trial registration: NCT02679807, study complete). Findings The first cohort of volunteers was randomized on March 14, 2016 and the last (5th) cohort was randomized on March 12, 2018. Sixty-three (56%, 95% CI [47%; 66% ]) of the 112 subjects in the active group and 6o (50%,95% CI [41%; 59%]) of the 120 subjects in the placebo group had a protocol-defined rhinovirus-associated illness (chi(2)=0.91, p=0.34). The point estimate of the difference in illness (active-placebo) is 6.3% (95% CI -6.7;19.1). There were no adverse events that were judged as definitely or probably related to the study product. Interpretation In this study there was no effect of orally administered Bl-04 on the occurrence of RV-associated illness. (C) 2021 The Author(s). Published by Elsevier Ltd.