A quarantine zone for Covid-19 patients in the Da Nang Hospital in Da Nang, central Vietnam, March 2020. Photo by VnExpress/Nguyen Dong.

"The three patients have recovered and are qualified to be discharged in accordance with the Ministry of Health's protocol," Nhan said, adding that all three have tested negative for the coronavirus three times in a row.

The two British citizens were on Vietnam Airlines VN54 flight flew from London and landed March 2 in Hanoi. At least 16 people on that flight have been confirmed to be infected with the Covid-19 virus, including a flight attendant.

The Brits were confirmed Covid-19 positive on March 8.

The other patient, a Vietnamese woman who works as a saleswoman in an electronics shop in Da Nang's Hai Chau District, has also recovered. She'd come into direct contact March 4 with the British men who came to the shop as customers, before being confirmed to be infected herself on March 10.

The patients were treated in accordance with procedures and regimen laid out by the Health Ministry. The hospital was disinfected to prevent cross-infection among medical workers, Nhan said.

Da Nang City has confirmed six Covid-19 cases so far. The three active cases left are an American man confirmed infected on March 18, a 24-year-old Vietnamese woman confirmed infected on March 23, and a 27-year-old Vietnamese woman confirmed infected on March 25. None of the three have any severe symptoms, Nhan said.

Vietnam has recorded 153 Covid-19 cases in total, of whom 17 have been discharged from hospitals. Among the active cases, 37, including the latest three recoveries, have tested negative between one and four times.

Many of the currently active cases are Vietnamese nationals returning from Europe and the U.S. and foreigners visiting from the same regions.

The Covid-19 pandemic has killed more than 22,100 people globally after spreading to 198 countries and territories.