biostudies-literatureLiu LTNational Health Research Institutes, TaiwanMinistry of Health and Welfare, TaiwanNational Health Research InstitutesMinistry of Health and Welfare624-636https://www.ebi.ac.uk/biostudies/studies/S-EPMC11895958biostudies-literatureUnknown39(6)In Taiwan, coronavirus disease 2019 (COVID-19) involving the delta variant occurred after that involving the alpha variant in 2021. In this study, we aimed to analyze the Delta variant. A total of 318 patients in Taiwan infected with delta variants were identified. The case fatality rate (CFR) of patients infected with delta variants was 0.94% in Taiwan compared with that of those infected with alpha variants (5.95%). The possible reasons for the low CFR might be hybrid immunity due to infection and rapid promotion of the COVID-19 vaccination program during the alpha variant outbreak. We identified three 21J delta variants. Two long gene deletions were detected in these severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) isolates: ORF7aΔ91 in KMUH-8 and SpikeΔ30 in KMUH-9. ProteinThe Kaohsiung journal of medical sciencesThe identification and phylogenetic analysis of SARS-CoV-2 delta variants in Taiwan.PMC11895958NHRI‐110A1‐MRCO‐03212101MOHW109‐TDU‐B‐212‐114006MOHW110-TDU-B-212-124006MOHW109-TDU-B-212-114006NHRI-110A1-MRCO-03212101MOHW110‐TDU‐B‐212‐124006Tsai CYChu JJHHwang SJChuang WLChong IWTsai JJLin PCChen LJHsu MCChen CHLiu LTfalseThe identification and phylogenetic analysis of SARS-CoV-2 delta variants in Taiwan.In Taiwan, coronavirus disease 2019 (COVID-19) involving the delta variant occurred after that involving the alpha variant in 2021. In this study, we aimed to analyze the Delta variant. A total of 318 patients in Taiwan infected with delta variants were identified. The case fatality rate (CFR) of patients infected with delta variants was 0.94% in Taiwan compared with that of those infected with alpha variants (5.95%). The possible reasons for the low CFR might be hybrid immunity due to infection and rapid promotion of the COVID-19 vaccination program during the alpha variant outbreak. We identified three 21J delta variants. Two long gene deletions were detected in these severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) isolates: ORF7aΔ91 in KMUH-8 and SpikeΔ30 in KMUH-9. Protein2023-01-01T00:00:00Z2023 Jun2026-06-02T22:32:43.859Z2026-05-28T03:05:39.198ZS-EPMC118959583695152910.1002/kjm2.12665