After the coronavirus disease 2019 (COVID-19) emergency, there has been a search for antiviral drugs able to cure or ameliorate COVID-19 symptoms. In hospitalized patients requiring respiratory support several drugs have proved to reduce mortality [1–2] or shorten the time to recovery [3]. For outpatients with mild to moderate COVID-19, nirmatrelvir is an orally administered SARS-CoV-2 main protease inhibitor with potent pan–human-coronavirus activity in vitro. It is co-administered with a low dose (100 mg) of ritonavir.
