What type of study is this?

This is a Meta-Analysis study (also classified as: Systematic Review).

May 6, 2026Open Access

The Efficacy of Probiotics in Treating Upper Respiratory Tract Infections, Allergic Rhinitis, and Chronic Rhinosinusitis: A Systematic Review and Meta-Analysis

AAArezki AzziImam Mohammad ibn Saud Islamic University AAAssaf S. AlotaibiImam Mohammad ibn Saud Islamic University MAMuath S. AlamriImam Mohammad ibn Saud Islamic University

Key Points

To assess the clinical efficacy of probiotics in treating upper respiratory tract infections, allergic rhinitis, and chronic rhinosinusitis.
Conducted a PRISMA-guided systematic review and meta-analysis of randomized controlled trials.
Evaluated oral or topical probiotics for URTIs, AR, or CRS across multiple databases.
Extracted disease severity, episode incidence, duration of illness, and symptom scores.
Certain probiotic strains reduced symptom duration and antibiotic use in URTIs but showed non-significant pooled incidence reduction.
Probiotics improved quality of life and reduced TNSS in allergic rhinitis with evidence of immune marker changes.
Insufficient evidence available for chronic rhinosinusitis, with findings reported descriptively.

Abstract

Background: Upper respiratory tract infections (URTIs), allergic rhinitis (AR), and chronic rhinosinusitis (CRS) are prevalent and burdensome inflammatory disorders. Probiotics may modulate immune responses via gut–respiratory axis signaling, but their clinical efficacy across these conditions remains uncertain and highly heterogeneous. Methods: We conducted a PRISMA-guided systematic review and random-effects meta-analysis of randomized controlled trials (RCTs) evaluating oral or topical probiotics for URTIs, AR, or CRS (MEDLINE, EMBASE, CENTRAL, and Web of Science; inception to July 2025). Disease severity category (acute, subacute, chronic), episode incidence, and duration of illness were extracted alongside symptom scores. Risk of bias was assessed using the Cochrane RoB 2 tool, and certainty of evidence was graded using the GRADE framework. Results: Thirty-two RCTs were included. In URTIs, certain strains e.g., Lactiplantibacillus plantarum DR7, Lactobacillus rhamnosus GG reduced symptom duration and antibiotic use; however, the pooled incidence reduction was non-significant (RD = −0.07; 95% CI: −0.23 to 0.09; p = 0.38), with very high heterogeneity (I2 = 93.12%), limiting interpretability. In AR, probiotics reduced TNSS and improved quality of life (SMDs −0.72 to −2.30) in individual trials supported by immune marker changes e.g., increased IL-10, decreased IgE. In CRS, only two small trials—differing in delivery route (topical vs. oral), CRS phenotype, and publication era (2009 and 2017)—with conflicting effect directions were identified; formal meta-analysis was not performed given insufficient and methodologically heterogeneous data, and CRS findings are reported descriptively only. GRADE certainty ranged from very low (URTI incidence) to low (AR symptoms, URTI illness burden). Conclusions: Probiotic effects appear strain- and condition-specific. URTI pooled incidence data are unreliable due to extreme heterogeneity; individual strains show consistent benefits on illness burden and AR symptoms/quality of life. Evidence for CRS is insufficient for meta-analytic conclusions; findings are reported descriptively pending adequately powered dedicated trials. Strain-targeted RCTs with standardized outcomes, formal GRADE appraisal, and adequate power are needed before clinical recommendations can be made.

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