Of the three domestic cases is a Hanoi man residing in Hoai Duc District.
Tagged "patient 785," he visited Da Nang with his family from July 16 to 20.
He started coughing on August 3. He was admitted to Hanoi’s National Hospital for Tropical Diseases three days later and was confirmed infected the next day.
The remaining two, numbered 768 and 787, are residents in central Quang Ngai Province which stands nearby Da Nang.
Both are family members of previous infected cases and had come into close contact with them. They are diagnosed with Covid-19 when in isolation.
Two imported cases are patients 788 and 789.
On Wednesday, they entered Vietnam from Mexico via a special flight that transited in Japan. Upon entry, they were quarantined at a military facility in Khanh Hoa Province, home to the resort town of Nha Trang.
Their tests turned out positive on Thursday.
The new additions have raised Vietnam’s Covid-19 tally to 789, including 384 active cases. 10 patients have died and the rest have all recovered.
Since July 25 when locally transmitted cases returned to Vietnam after more than three months, 333 of such cases have been added, spreading in 13 cities and provinces, including Hanoi and Ho Chi Minh City. All are linked to the epicenter Da Nang.
The global Covid-19 death toll has climbed to more than 772,700.