This study investigates the effects of sustained Losartan monotherapy (ARB) and combination Losartan + Lisinopril (ARB + ACEi) on viral replication, inflammation, lung function, and clinical measures of disease severity in a murine model of severe COVID-19 involving humanized ACE2 transgenic mice infected with SARS-CoV-2 Wuhan strain. The gene discussed is ACE2; the disease is COVID-19.