Hanoi continued to record the highest number of infections with 2,945 cases, followed by Da Nang with 973 and Hai Phong with 745.
The national tally reached 2,126,444 , including 135 infections of Omicron.
On the day, the country saw 153 deaths from the disease. The death toll now hits 35,972.
There are 4,680 patients in critical conditions, including 604 requiring invasive ventilation and 21 on ECMO support.
A total 3,512 patients were given the all-clear, taking the total number of recoveries to 1,800,692.
By January 21, the country had injected 174.9 million doses of vaccines to date, with 73.7 million people now fully inoculated, while 22.3 million booster shots and third shots of Abdala vaccine had been administered.