Moreover, it remains to be elucidated whether the predominant source of SARS-CoV-2 for subsequent intestinal infections are previously infected-mucosal cells in the upper airways such as pharyngeal- and nasal epithelial cells, in which very high levels of ACE2 expression16 and SARS-CoV-2 virus can be detected in infected individuals43 and which might also facilitate the oral ingestion of virus or whether SARS-CoV-2 can also primarily infect intestinal cells after oral ingestion of SARS-CoV-2 by circumventing infections of the upper airways. Here, ACE2 is linked to infection.