Probiotics for respiratory tract infections in children attending day care centers-a systematic review.

Abstract

Probiotics have been suggested to have a preventive effect on respiratory tract infections (RTIs), but limited evidence exist on strain-specific effects. The main aim of this systematic review and meta-analysis was to evaluate strain-specific probiotic effects on RTIs in children attending day care. We included 15 RCTs with 5121 children in day care settings (aged 3months to 7years), but due to high diversity in reported outcomes, different number of RCTs were available for evaluated outcomes. Twelve RCTs (n = 4527) reported results which could be compared in at least one outcome of the meta-analysis. Compared to placebo, Lactobacillus rhamnosus GG (LGG) significantly reduced duration of RTIs (three RCTs, n = 1295, mean difference - 0.78days, 95% confidence interval (CI) - 1.46; - 0.09), whereas no effect was found on other evaluated outcomes. Based on the results from two studies (n = 343), Bifidobacterium animalis subsp. lactis BB-12 showed no effect on duration of RTIs or on absence from day care. Meta-analyses on other strains or their combination were not possible due to limited data and different outcome measures.Conclusion: LGG is modestly effective in decreasing the duration of RTIs. More RCTs investigating specific probiotic strains or their combinations in prevention of RTIs are needed. What is known: • Previously published systematic reviews have suggested that probiotics may have a preventive effect on respiratory infections, but limited data exist on strain specific effects. What is new: • This systematic review showed that use of Lactobacillus rhamnosus GG modestly reduces the duration of respiratory tract infections.