The antiviral effects and underlying mechanisms of probiotics on viral infections

In public health emergencies, viral diseases like influenza and COVID-19 have become a major concern. One of the proposed responses to this concern is the use of probiotics. Probiotics have a potent role in arming our bodies to combat viral infections. They affect the innate and adaptive immune systems in various ways. Accumulating studies has shown that probiotics can reduce the possibility of infection or the duration of respiratory symptoms by modulating the functions of the immune system. This review aims to summarize the impacts of probiotics on respiratory viral infections and their potential antiviral mechanisms. Therefore, we herein discussed probiotics in relation to lung immunity, distinct types of respiratory viral infections (VRIs), including influenza, rhinoviruses, respiratory syncytial virus, and upper respiratory viral infections, and lastly, probiotics and their effects on COVID-19. However, more studies are needed to explore the antiviral mechanisms of probiotics.