The three localities with the highest number of new cases were Hanoi with 1,425 cases, northern Yen Bai Province with 895 cases, and northern Vinh Phuc Province with 813 cases.
Of the day's tally, 15,555 cases were detected in the community.
The Covid-19 death toll in Vietnam rose to 42,927 with the confirmation of 23 deaths Monday.
The Health Ministry also confirmed 6,417 recoveries the same day, bringing the total number of recovered cases so far to 8,863,044.
Over 77.3 million people of Vietnam's 96 million population have been vaccinated with two doses, and more than 51.5 million have received the third dose.