Hanoi led the tally with 2,940 cases, followed by Hai Duong with 1,906 and Nam Dinh with 1,894.
On Sunday, 84 deaths were confirmed, raising the death toll to 38,946, or 1.6 percent of the total infections.
The number of recoveries has increased to 2,226,754 after 7,815 cases were recovered on the same day.
Vietnam has recorded 197 Omicron infections to date, including 97 in HCMC.
74.7 million have received their second shots and 31.7 million have received their third shots.