Probiotics and COVID-19: is there any link?

Understanding mechanisms of the novel SARS-CoV2 infection and progression can provide potential novel targets for prevention and/or treatment. This could be achieved via the inhibition of viral entry and/or replication, or by suppression of the immunologic response that is provoked by the infection (known as the cytokine storm). Probiotics are defined as 'live microorganisms that, when administered in adequate amounts, confer a health benefit on the host'. There is scarcity of evidence about the relationship between COVID-19 and gut microbiota. So, whether or not these supplements can prevent or ameliorate COVID-19-associated symptoms is not fully understood. The aim of this study is to provide an indirect evidence about the utility of probiotics in combating COVID-19 or its associated symptoms, through the review of its antiviral and anti-inflammatory properties in vitro, animal models and human trials. SIGNIFICANCE AND IMPACT OF THE STUDY: The role of probiotics in alleviation of the novel COVID-19 has not been established. This review provides an insight about the anti-inflammatory, antiviral effects of probiotics in vitro, animal models and human. The latter can provide an indirect evidence and/or hypothesis-driven approach to investigate the use of probiotics as adjunctive therapy in the prophylaxis and/or alleviation of COVID-19 symptoms.