ACE2 and COVID-19: The predominant mechanism for entry of SARS-CoV-2 into host cells requires recognition of the host cell angiotensin converting enzyme 2 (ACE2) receptor by the viral spike protein and proteolytic activation of the viral spike protein by the host cell transmembrane protease 2 (TMPRSS2).1 Pharmacologic targeting of TMPRSS2 or ACE2 might reduce SARS-CoV-2 viral entry and severity of COVID-19.