The Ha Nam patients are family members of two people who were confirmed Covid-19 cases on Thursday.
The Hanoi patients are co-workers at Bac Thang Long Industrial Zone. They have had had contact with a previously confirmed patient, who is a friend and had joined with patient 2899, a man who tested positive with the novel coronavirus after completing a two-week quarantine, in a party on April 22.
After over a month of no community transmissions, Vietnam has recorded 13 new local cases since Thursday, including cases in HCMC and the northern Hung Yen Province who also had contact with patient 2899.
Patient 2899 is a migrant worker coming back from Japan and entered quarantine in Da Nang earlier this month. After completing two-week quarantine on April 21, he flew home in Ha Nam and developed symptoms two days later, before testing positive for the coronavirus.
Vietnam has confirmed 924 local cases since January 27.
The country has recorded 2,928 Covid-19 cases to date, including 2,516 recoveries and 35 deaths.
The Ministry of Health has warned of high chances of contagion from illegal border entrants and urged people to take protective measures.
Over 506,000 people have been vaccinated as of Friday.