A broader cellular protease inhibitor such as alpha-1 antitrypsin (AAT), used to treat severe AAT human deficiency and currently under clinical study for COVID-19 due to its anti-inflammatory potential, has already shown capacity to limit SARS-CoV-2 entry in cells expressing TMPRSS2 (Münch, 2020; Oguntuyo et al., 2020). The gene discussed is SERPINA1; the disease is COVID-19.