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 clinical 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 60 (50%,95% CI [41%; 59%]) of the 120 subjects in the placebo group had a protocol-defined rhinovirus-associated illness (χ2=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.
Funding: Danisco Sweeteners Oy (now IFF Health & Biosciences).
Keywords: innate immunity; probiotic; rhinovirus; upper respiratory infection.
© 2021 The Author(s).