ABSTRACT
Coronavirus 2, universally known as SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), was identified only a year ago as the causative agent of a new acute respiratory disease: the "coronavirus disease 2019" (COVID-19). The pathognomonic symptoms of COVID-19 are cough, fever, and dyspnea. To date, only two studies have been published to assess whether there are differences between the respiratory microbiota of healthy people and those with COVID-19, and in both cases the sample size was small. This chapter details these two studies. In any case, COVID-19 contains numerous aspects that constitute clear targets for the application of probiotics: the presence of diarrhea and other digestive symptoms in a high percentage of cases;modulation of the immune and inflammatory response to the virus;and so on. © 2023 John Wiley and Sons Ltd. Published 2023 by John Wiley and Sons Ltd.