ACE2 and susceptibility to pneumonia measurement: However, disruption of ACE2 function occurs during severe acute respiratory syndrome coronaviruses 1 and 2 (SARS-CoV and SARS-CoV-2, respectively) infection, when the ACE2 receptor is bound by viral spike protein leading to MAPK activation and the production of proinflammatory cytokines and causing pneumonia or even acute respiratory distress syndrome (ARDS) [8].