Safety and efficacy of probiotic supplements as adjunctive therapies in patients with COVID-19: A systematic review and meta-analysis

Background and aimsOral probiotic supplementation may be a beneficial adjunctive therapy for patients with symptomatic COVID-19. However, its safety and efficacy are unclear. We aimed to investigate how probiotic supplementation impacts COVID-19 symptom trajectory and patient outcomes by conducting a systematic review and meta-analysis of randomized controlled trials (RCTs). MethodsRCTs randomizing patients with COVID-19 to probiotics were searched in PubMed Central, Embase, CINAHL, and Cochrane Library from inception to July 31, 2022. We performed a random-effects pairwise meta-analysis for all outcomes using the restricted maximum likelihood (REML) estimator. We used the GRADE approach to assess the certainty of the evidence. ResultsA total of 1027 participants from eight RCT studies were included in the meta-analysis. Probiotic supplements probably reduce the incidence of diarrhea (RR 0.61 [0.43 to 0.87]; moderate certainty) and probably reduce cough or dyspnea compared to placebo/standard care (RR 0.37 [0.19 to 0.73]; moderate certainty). Probiotic supplements may improve composite endpoint measured by clinical escalation or mortality compared to placebo (RR 0.41 [0.18 to 0.93]; low certainty evidence); however, they may not significantly reduce the need for clinical escalation (RR 0.57 [0.31 to 1.07]; low certainty evidence) or mortality (RR 0.50 [0.20 to 1.29]; low certainty evidence). In addition, the probiotic supplement is associated with reduced adverse events (RR 0.62 [0.46 to 0.83]; moderate certainty). ConclusionEarly probiotic supplement is a safe and effective adjunctive therapy that reduces the risk of symptoms and health care burden related to COVID-19 across all severity types.

Automated summary

This study conducted a systematic review and meta-analysis to investigate the impact of probiotic supplementation on COVID-19 symptom trajectory and patient outcomes. The results showed that probiotic supplements can reduce the incidence of diarrhea, cough or dyspnea, and adverse events, and may improve the composite endpoint measured by clinical escalation or mortality.