Among children with upper respiratory tract infections (URTIs), at-home administration of a probiotic mixture for two weeks shortened the duration of fever by about two days compared with those who received placebo, results from a recent single-center, randomized study showed.
“In general, the positive effects of probiotics have been associated with the prevention and treatment of gastrointestinal disorders,” the study’s corresponding author, Carlo Agostoni, MD, of the pediatric unit at the Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico in Milan, Italy, said. “This study may represent the starting point of a newer area of research linking probiotics to a favorable influence on respiratory disorders, particularly in young infants. Accordingly, the positive effect should be attributed to the modulation of the immune system, mediated by the changes in the gut flora.”
For the trial, published in JAMA Network Open,the researchers evaluated the efficacy of a commercially available probiotic mixture containing Bifidobacterium breve M-16V, Bifidobacterium lactis HN019, and Lactobacillus rhamnosus HN001 in shortening fever duration among children with URTIs.1 The study population included 128 children between 28 days and 4 years of age who presented with fever and were diagnosed with URTIs by a pediatrician in the pediatric emergency department of the Policlinico di Milano between November 19, 2021, and June 20, 2023. Of the 128 children, 63 were randomized to receive a daily single dose of 0.5 mL probiotic mixture at home for 14 days, while the remaining 65 were randomized to receive a daily single dose of 0.5 mL placebo mixture once daily for 14 days. The study measured fever duration, defined as number of days between the first and last days with fever.
Per the study protocol, providers were instructed to measure rectal body temperature at least three times daily (morning, afternoon, and evening or night) until fever disappearance, which was defined as a rectal temperature less than 38.5 °C for at least 24 hours without the use of antipyretics.
The mean age of study participants was 2.5 years, 54% were male, 79% were white, and 26% were receiving antibiotics at enrollment. Of the 128 children, 70 (55%) fully adhered to the treatment protocol, 17 (13%) partially adhered, and 41 (32%) dropped out of the trial.
Children in the probiotic group experienced a statistically significantly shorter duration of fever compared with those in the placebo group (a median 3 vs 5 days, P < .001; adjusted risk ratio, 0.64; 95% CI, 0.51- 0.80). The most common reported adverse events were constipation (12 [14%]), followed by diarrhea (four [5%]), and abdominal pain (five [6%]), but their distribution did not significantly differ between the probiotic and placebo groups. Among children who received antibiotics at enrollment, none in the probiotic group and three in the placebo group developed diarrhea.
Dr. Agostoni acknowledged certain limitations of the analysis, including its single-center design and the fact that caregivers measured the temperature of study participants at home. “The most difficult point is to exclude any bias in the parental reporting,” he said. He also pointed out that the treatment group received a combination of three probiotic strains, “so it would be of interest to know whether just one probiotic strain, or more probiotic strains, might be at the origin of the effects.”
References
1. Bettocchi S, Comotti A, Elli M, et al. Probiotics and fever duration in children with upper respiratory tract infections: A randomized clinical trial [published correction appears in JAMA Netw Open. 2025 May 1;8(5):e2516123. doi:10.1001/jamanetworkopen.2025.16123.]. JAMA Netw Open. 2025;8(3):e250669. Published March 3, 2025. doi:10.1001/jamanetworkopen.2025.0669.
