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Upper respiratory tract infections (URTIs) are among the most common reasons children see a doctor—and for many families, fever is the most distressing symptom. While integrative care offers tools for supporting immune resilience, new research suggests that specific probiotic strains may also help reduce the burden of acute illness. A recent randomized controlled trial identifies a promising trio of microbes that significantly shortened fever duration in young children.
Fever is a hallmark of the body’s immune response to infection—but prolonged fever, especially in infants and toddlers, can drive parental anxiety, disrupt sleep, and increase antipyretic use. While probiotics are well-known for their gut and immune benefits, most clinical trials have focused on prevention. Could they also offer therapeutic value once illness has already begun?
A new randomized clinical trial published in JAMA Network Open (November 2024) says yes—at least for the right strains.
Researchers investigated whether daily supplementation with a precise combination of probiotic strains could reduce fever duration in children aged 28 days to 4 years who presented with febrile URTIs.
This double-blind, placebo-controlled trial enrolled 128 children at a tertiary pediatric hospital in Milan, Italy. Participants were randomized to receive either a probiotic mixture or placebo once daily for 14 days, beginning at the onset of febrile symptoms.
The probiotic formulation included three well-studied strains:
All strains were delivered in a 0.5 mL daily oral dose, with viability and strain specificity confirmed by the manufacturer.
The primary outcome was fever duration, defined as the total number of days with a temperature ≥38.5°C, measured at home and verified by study staff.
The probiotic group experienced a significant reduction in fever duration compared to placebo:
âžź Median fever duration: 3 days in the probiotic group vs. 5 days in the placebo group
➟Adjusted Risk Ratio (aRR): 0.64 (95% CI: 0.51–0.80), indicating a 36% reduction in total fever days
No serious adverse events were reported, and minor GI symptoms (e.g., constipation, mild abdominal pain) were rare and comparable across both groups.
While the study did not track additional clinical outcomes such as antibiotic use or hospitalization, it provides compelling evidence that targeted probiotic strains may help modulate the course of acute infection, not just prevent it.
Each of the strains used in the trial has immunological activity documented in previous studies:
➣ B. breve M‑16V has been shown to reduce pro-inflammatory cytokines and support gut-immune cross-talk, particularly in infants.
➣ B. lactis HN019 modulates both innate and adaptive immunity, enhancing NK cell activity and supporting mucosal defenses.
➣ L. rhamnosus HN001 has been linked to reduced incidence of atopic disease and is known for its role in immune tolerance and Th1/Th2 balance.
Together, these strains likely act through multiple mechanisms—dampening excessive inflammation while preserving the body’s ability to clear infection. Their use as a combination is synergistic and reflects the kind of thoughtful strain selection that should underpin probiotic therapeutics.
For clinicians working with young children, especially in the fall and winter months when URTIs are ubiquitous, this study offers an actionable strategy:
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