A systematic search of the following terms have been searched in PubMed database: “(name of the drug)” or “(name of the drug class)” or “(hormone)” + “COVID” or “SARS-CoV-2” or “lung injury” or “ARDS” or “viral” or “renin-angiotensin system” or “renin-angiotensin-aldosterone system” or “TMPRSS2” or “ACE2” or” RAAS”. The gene discussed is ACE2; the disease is acute respiratory distress syndrome.