All 57 new cases have been isolated prior. Twenty of them are in Ho Chi Minh City, 19 in Bac Giang Province, 12 in Bac Ninh Province, five in Hanoi and one in Lang Son Province.
Also on Wednesday, 87 patients were discharged, bringing the total recoveries to date to 3,636.
The country has recorded 6,385 local cases in the latest Covid-19 wave starting from April 27.
Sixteen localities have gone 14 days without any new Covid-19 case.