46 cases were recorded in Bac Giang and one each recorded in Tay Ninh, Dien Bien and Hanoi's locked down National Hospital for Tropical Diseases.
All the cases in the northern Bac Giang Province are associated with outbreaks at the province's industrial parks, while the rest of the cases have made contact with existing coronavirus patients.
The case in Tay Ninh in particular, a two-year-old boy, is associated with a previously confirmed patient in HCMC.
Vietnam's latest Covid-19 wave has seen 3,644 infections over the past month. 34 cities and provinces have recorded infections.