Of the seven patients, tagged from 2413 to 2424, five had come into close contact with previously confirmed cases and been quarantined, the Health Ministry said.

One patient was found infected through a screening test and the remaining one after following up on suspected symptoms.

They are being treated in the northern province's field hospitals.

The health ministry also confirmed one imported case Thursday, a 25-year-old resident of Can Tho City. She had entered the country via Moc Bai international border gate in the southern province of Tay Ninh, and was quarantined upon arrival.

Hai Duong, around 60 kilometers from Hanoi, is implementing a 15-day social distancing campaign starting February 16 to stem the spread of the coronavirus. Authorities have requested residents to stay home and only go out to buy necessities like food and medicine or for emergencies.

The new outbreak began Jan. 28 after Vietnam went 55 clean days in a row. Since then, a total of 827 community transmissions have been recorded in 13 localities, including Hanoi and Ho Chi Minh City. With 636 cases, Hai Duong is now the biggest Covid-19 hotspot, followed by Quang Ninh (61) and HCMC (36).

The national tally has gone up to 2,420, with 35 deaths.

Ten containers with 117,600 Covid-19 vaccine doses produced by the AstraZeneca company were unloaded at HCMC's Tan Son Nhat International Airport Wednesday morning.

They would be administered with priority given to those on the frontlines of the pandemic fight, including medical workers, doctors, nurses, contact tracers and officials of Covid-19 prevention and control committees.

Vietnam is planning a mass Covid-19 vaccination campaign for its 98-million population.