Effect of Probiotics on COVID-19 Infection: A Systematic Review

Background and Aim: Scientific evidence has shown that SARS-CoV-2 can infect intestinal epithelial cells and probiotics are capable of inducing immune responses against respiratory viruses. Since there have been no specific guidelines or treatment for the patients with COVID-19, we performed this systematic review of studies to investigate the effect of probiotics on COVID-19 infection. Materials and Methods: This study included relevant English original articles in the international databases of PubMed and Scopus using the keywords of "severe acute respiratory syndrome", "coronavirus 2", "sars-cov-2", "2019 novel coronavirus", "2019 nCoV", "new coronavirus, COVID-19", "probiotics" and the "combination of these keywords" between the beginning of 2018 and 20 July 2022. Results: A total of 424 articles were found among which 6 articles met the inclusion criteria for this study. The findings of this study showed that fever, cough, shortness of breath and diarrhea were the main symptoms of the patients with COVID-19. Also, consumption of probiotics using bacterial formula ( Streptococcus thermophilus , Lactobacillus acidophilus , and Bifidobacterium spp) can be an effective treatment option to reduce the incidence of secondary infections and modulate immunity in the patients with SARS-CoV-2 infection. Conclusion: It seems that administration of probiotics in order to modulate the intestinal-lung immune axis as an adjunctive treatment can be useful for prevention and management of COVID-19 infection.