Probiotics can have an impact on feverish respiratory infections

06.2025
Author Dr. Martin Claßen, Bremen

Feverish respiratory infections, mostly caused by viruses, are one of the major issues at paediatric clinics in the winter months. Parents often ask for help, but apart from supportive measures, there is little that doctors can actively do. 
A study was conducted in Milan on children aged between 28 days and 4 years to investigate whether a mix of probiotics, consisting of Bifidobacterium breve M-16V, Bifidobacterium lactis HN019 and Lactobacillus rhamnosus HN001, can have an effect on the progression of these infections. The study looked at 128 patients immediately after they had visited Accident & Emergency and been diagnosed with a respiratory infection (69 male [54%]; average age 2.5 years). It was double-blind and randomised: over 14 days, 65 (51%) were given a placebo, and 63 were given a mix of probiotics.
The median duration of the fever was significantly lower in the probiotic group (3 days [IQR 2-4]) versus 5 days [IQR 4-6], making the adjusted risk rate 0.64 95% CI, 0.51-0.80). The group comparison showed no significant side effects.

Comment: The fact that this intervention with probiotics led to an average reduction in the duration of the fever of 2 days is remarkable, but of course it must be confirmed by other study centres. As with other studies involving probiotics, the devil is in the detail. Probiotic preparations are fundamentally difficult to compare, and the stems and concentrations used must be examined very carefully. The preparation used here is sold in Italy. 
Effects on the humoral immune system, direct antiviral effects and influences on inflammatory messengers are discussed as potential mechanisms of action. Influences on other symptoms of infection were not investigated. Fortunately, there were no significant differences with regard to gastrointestinal side effects. 
If parents of a child with a respiratory infection are asking what they can do, I would at least not advise against giving their child probiotics at the moment.
 

Reference:
Bettocchi, S, Comotti, A, Elli, M, De Cosmi, V, Berti, C, Alberti, I, Mazzocchi, A, Rosazza, C, Agostoni, C, Milani, GP. Probiotics and Fever Duration in Children With Upper Respiratory Tract Infections: A Randomized Clinical Trial. JAMA Netw Open. 2025;8(3):e250669. DOI: 10.1001/jamanetworkopen.2025.0669