Among the 40 domestically-transmitted cases, 24 were found in Bac Giang province, 10 in the neighbouring province of Bac Ninh, three in Ho Chi Minh City, and one each in Lang Son, Hai Duong and Vinh Phuc provinces.
The latest cases have brought the national count of domestic infections to 3,331. A total of 1,761 cases have been detected since the new wave of the pandemic started in the country on April 27.
Two patients were given the all-clear on May 20, raising the number of recoveries in the country to 2,689. Meanwhile, fatalities related to the pandemic reached 39.
Among the patients under treatment, 63 have tested negative for the coronavirus SARS-CoV-2 once, 34 twice, and 23 thrice.
As many as 121,010 people who had come into close contact with COVID-19 patients or entered Vietnam from pandemic-hit areas are now under medical monitoring nationwide.
