The Immunomodulatory Effects of Probiotics on Respiratory Viral Infections: A Hint for COVID-19 Prophylaxis?

The most common human illness is upper respiratory tract infection. It causes a high rate of absenteeism from school and work, as well as decreased efficiency and productivity. Individuals with chronic diseases such as asthma, as well as preterm infants and the elderly, are more susceptible to viral respiratory tract infections. Preliminary studies have shown that probiotics, reduce allergic diseases, asthma and strengthen the immune system, which reduces viral infections. In this mini-review we look at how probiotics and prebiotics affect viral respiratory tract infection. Functional foods containing well-defined probiotic strains, such as probiotic milk or yogurt, can reduce the risk of catching a cold and represent an easy, healthy, reliable, and accessible method for preventing respiratory infections, especially in developing countries. More research is needed to determine the role of probiotics and prebiotics in the treatment and prevention of RTIs, as well as to determine whether any susceptible subgroups of respiratory diseases exist and how these subgroups benefit from probiotic supplementation.