Most of the new cases were detected in Ho Chi Minh City, at 1,475.
It was followed by the southern province of Tay Ninh with 874 cases and Soc Trang with 781 cases.
In the past 24 hours, 230 Covid-19 patients have died, including 75 in HCMC.
Since the pandemic started last year, the death toll in Vietnam has climbed to 26,930 or 2 percent of all infections.
In the latest wave that hit the country in late April, more than 1.35 million cases have been reported and 1.03 million of them have recovered.
So far 55.5 million people have been fully vaccinated.
One Tuesday a 15-year-old boy in the northern province of Son La had become the 4th child in Vietnam to die after being vaccinated with the Pfizer vaccine.