ACE2 and COVID-19: One of the key factors in preventing the spread of coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is the ability of the human immune system to produce neutralizing antibodies that could successfully block the SARS-CoV-2 spike (S) protein (in specific regions) and prevent its binding to the angiotensin-converting enzyme 2 (ACE2) receptor.