Spatiotemporal Evolution of SARS-CoV-2 Alpha and Delta Variants during Large Nationwide Outbreak of COVID-19, Vietnam, 2021.
Tam NT., Anh NT., Tung TS., Thach PN., Dung NT., Trang VD., Hung LM., Dien TC., Ngoc NM., Van Duyet L., Cuong PM., Phuong HVM., Thai PQ., Tung NLN., Man DNH., Phong NT., Quang VM., Thoa PTN., Truong NT., Thao TNP., Linh DP., Tai NT., Bao HT., Vuong VT., Nhung HTK., Hong PND., Hanh LTP., Chung LT., Nhan NTT., Thanh TT., Hung DT., Mai HK., Long TH., Trang NT., Thuong NTH., Hong NTT., Nhu LNT., Ny NTH., Thuy CT., Thanh LK., Nguyet LA., Mai LTQ., Thuong TC., Nga LH., Thanh TT., Thwaites G., Rogier van Doorn H., Chau NVV., Kesteman T., Van Tan L., OUCRU COVID-19 Research Group2 None.
We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions.