“…The respective activities, however, increased in the recovery phase, and the authors concluded that serum ACE activity could be potentially used as a marker reflecting COVID-19 severity, since low activity was associated with the severity of COVID-19 at baseline, and the activity increased with the remission of the disease [244]. Likewise, others have shown that serum ACE activity was lower in patients with COVID-19 vs. controls [245,246]. In another study, serum ACE activity upon hospital admission did not reflect disease severity [247], while our group demonstrated that serum ACE activity was similar in COVID-19 ARDS and non-ARDS patients [236].…”