ACE2 and COVID-19: The protein has been shown to protect from severe acute lung injury in mice.36 In addition, recombinant ACE2 has already been tested in Phase I and II human clinical trials and its safety and good tolerance by the patients have been well documented.37,38 The anti-SARS-CoV-2 activity of recombinant soluble ACE2 is evident in vitro.24–26 Furthermore, a clinical-grade human-ACE2 protein preparation, namely APN01, has entered Phase II clinical trial to treat COVID-19 in several countries (https://www.clinicaltrials.gov/ct2/show/study/NCT04335136?term=APN01&draw=2&rank=1).