The Effectiveness of Probiotics against Viral Infections: A Rapid Review with Focus on SARS-CoV-2 Infection

Viral infections have gained great attention following the rapid emergence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic around the globe. Even with the continuous research on developing vaccines and antiviral agents against various viral infections, no specific treatment or vaccine has been approved for many enteric or respiratory viral infections; in addition, the efficiency of currently available treatments is still limited. One of the most reliable and recommended strategies to control viral infections is prevention. Recently, intense studies are focusing on a promising approach for treating/preventing various viral infections using probiotics. As per the World Health Organization (WHO), probiotics can be defined as “live microorganisms which, when administered in adequate amount, confer a health benefit to the host.” The use of probiotics is a simple, cost-effective, and safe strategy to prevent viral infections, specifically; respiratory tract and intestinal ones, by different means such as stimulating the host’s immune response or modulating gut microbiota. In this rapid review, we emphasize the protective effects of probiotics against viral infections and proposed mechanisms for protection that might offer a novel and cost-effective treatment against current and newly discovered viruses like SARS-CoV-2.