Using the GISAID EpiCoV database, we identified 256 COVID-19 patients in Japan during March 31-December 31, 2023, who had mutations in the SARS-CoV-2 nonstructural protein 5 conferring ensitrelvir resistance. Ongoing genomic surveillance is required to monitor emergence of SARS-CoV-2 mutations that are resistant to anticoronaviral drugs.
Keywords: COVID-19; GISAID; Japan; SARS; SARS-CoV-2; antimicrobial resistance; coronavirus; coronavirus disease; ensitrelvir; respiratory infections; severe acute respiratory syndrome coronavirus 2; viruses; zoonoses.