Strain-Specific Effects of Early-Life Probiotic Supplementation on Respiratory Infections in Infants: A Systematic Review and Meta-Analysis
Probiotic or synbiotic supplementation in the first 24 months of life did not significantly reduce the risk of upper respiratory tract infections in infants.
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What the study showed
A meta-analysis of 9 RCTs found no significant reduction in URTI incidence (OR 0.95; 95% CI 0.47–1.95; I²=78%). A non-significant trend toward reduced risk of any RTI was observed (OR 0.66; 95% CI 0.35–1.25; I²=69%). High heterogeneity limits the interpretation of pooled estimates.
How it was done
Systematic review and meta-analysis of RCTs published between 2015 and September 2025, retrieved from PubMed/MEDLINE, Embase, and Scopus. Random-effects models were applied; risk of bias was assessed with Cochrane RoB 2 and evidence certainty with GRADE.
Risk of bias
Only 9 trials were included, with very high heterogeneity (I²=69–78%), indicating substantial differences in strains, doses, and populations. The abstract was truncated, precluding access to subgroup analyses and the full GRADE assessment.
What this study does NOT prove
It cannot be concluded that specific strains are ineffective, nor that the null pooled effect reflects absence of benefit in particular subgroups.
In clinical practice
Available evidence does not support recommending probiotics for URTI prevention in infants. Strain-specific variability prevents clinical extrapolation from the pooled null effect.
Limitations
Only 9 trials were included, with very high heterogeneity (I²=69–78%), indicating substantial differences in strains, doses, and populations. The abstract was truncated, precluding access to subgroup analyses and the full GRADE assessment.
Technical appendix
Version history
- 1.0 · 2026-07-16 — Auto-generated under Evidence Standard v1.0
Paid access: structured summary from public metadata; consult the original study at the source.