Benefits of probiotic use on COVID-19: A systematic review and meta-analysis

SARS-CoV-2 is the virus that causes the new global pandemic, which has already resulted in millions of deaths, affecting the world's health and economy. Probiotics have shown benefits in a variety of diseases, including respiratory infections, and may be beneficial in the adjunctive treatment of COVID-19. This study analyzed the effectiveness of probiotics as adjunctive treatment in reducing symptoms of patients with COVID-19, through a systematic review with meta-analysis. The EMBASE (Elsevier), Pubmed, Scopus, Web of Science and International Clinical Trials Registry Platform (ICTRP) were searched through March 16, 2022. The risk ratio (RR) with 95% confidence intervals (CIs) was estimated using a fixed-effect model. RoB 2 and ROBINS I were used to assess the risk of bias of the included studies. Nine studies were included (7 clinical trials and 2 cohorts), of which three clinical trials comprised the meta-analysis. Results showed that probiotics were associated with a significant 51% reduction in symptoms reported by COVID-19 patients (RR 0.49, 95% CI 0.40–0.61). There was a significant improvement in cough (RR 0.56, 95% CI 0.37–0.83), headaches (RR 0.17, 95% CI 0.05–0.65), and diarrhea (RR 0. 33, 95% CI 0.12–0.96) of patients on probiotic therapy. These findings suggest that probiotic supplementation is effective in improving symptoms of COVID-19.