At least 21,000 people are undergoing rapid test swabs for the virus in the capital Hanoi after travelling to Danang.
The most recent cases were linked to three hospitals and two clinics in Danang, according to the health ministry, which overnight sent a task force of health experts, along with more than 1,000 health workers, to the city.
The Health Ministry said the latest fatalities included a 68-year old woman who was treated for blood cancer and a 61 year-old man who suffered septic shock and chronic kidney failure.More news: Bryan Cranston Reveals He Recovered from Coronavirus: ‘Keep Wearing the Damn Mask’
Authorities in Danang are building a 1,000-bed field hospital to ease the burden on the city's hospitals, four of which are under lockdown following a series of cases there.
Dr Luong Ngoc Khue, head of the country's Administration of Medical Examination and Treatment, said there are at least six other elderly patients with Covid-19 now in critical condition. More than 100,000 people have been confirmed to be infected with the coronavirus in the country.
Vietnam had been seen as a global success story in combating the coronavirus with zero deaths and no cases of local transmission for 99 days.More news: Eight still missing after US Marine amphibious vehicle sinks
The country of 96 million had gone 100 days without infection before an unexpected cluster of new cases of unknown origin surfaced in the popular central resort city of Danang a week ago.
By Saturday morning, Vietnam has recorded 558 Covid-19 cases, including 182 active patients after 373 have recovered.
The communist state has won praise for its handling of the virus - reporting just 509 infections in total, including those from the new wave, and no deaths despite sharing a long border with China. Similar tests are also conducted in business hub Ho Chi Minh City for returnees from Danang. The city on Friday began setting up a makeshift hospital in a sports auditorium and doctors have been mobilized from other cities to help.More news: Jonathan Isaac stood for the anthem over religious beliefs