It is therefore plausible that critically ill COVID-19 patients may have a disrupted gut barrier, also known as a “leaky gut” (47, –, 49, 70), which may allow SARS-CoV-2 to not only bind to ACE2 on the enterocytes but also exit the GI tract and enter the bloodstream, allowing it to access various organs expressing ACE2 throughout the body (Fig. 2). This evidence concerns the gene ACE2 and COVID-19.