ACE2 and COVID-19: The available research results indicate that: (a) ACE2, as one of the SARS-CoV-2 receptors, may play an important role in SARS-CoV-2 infection and progression of COVID-19; (b) SARS-CoV-2 infection may be one of the factors leading to a change in ACE2 activity and, consequently, to disorders of the RAA system.