Kidong Park, the WHO Representative in Vietnam, referring to the recent Covid-19 cases caused by local transmission in Da Nang and the nearby province of Quang Ngai, said: "We will not be surprised if Vietnam records more Covid-19 cases in the community in the upcoming time.

"It shows that the disease surveillance system has been working effectively, allowing it to find cases quickly and in time.

"We believe Vietnam will be able to quickly detect infection cases, track down suspected ones and locate the stricken areas to put down the outbreaks."

He was speaking at a meeting with the National Steering Committee on Covid-19 Prevention and Control in Hanoi Monday, Vietnam News Agency reported.

Since April 16 the country had gone 99 days without a single local case of infection.

But on July 25 a man in Da Nang was diagnosed with Covid-19, and then three more cases of community transmission were found the next day in the city and Quang Ngai.

On Monday, seven patients and four medical staff at the Da Nang Hospital tested positive.

Authorities are still searching for the source of infection of all 15 patients.

Until the new Covid-19 cases were discovered last weekend, the only others infected were citizens returning from abroad on repatriation flights organized by the government.

This reflects a "humanitarian policy which could reinforce people’s trust in the government," Park said.

WHO respects Vietnam’s decision to bring home hundreds more from stricken areas, including 219 from Equatorial Guinea, of whom more than half are infected, and 226 from Uzbekistan, of whom around 100 are infected.

On Tuesday morning a flight left for Equatorial Guinea from Hanoi along with a medical team.

Those in Uzbekistan are expected to be brought back early next month.

Since April Vietnam has operated more than 60 flights to bring home more than 16,000 nationals from over 50 countries and territories, the Ministry of Foreign Affairs said.

With dozens of new infections expected to be found in Da Nang, the steering committee has called on the Ministry of Health to have its personnel at hospitals and clinics in localities near the city to stand by to assist.

By Tuesday morning Vietnam had reported 431 Covid-19 cases, 66 of them active. The rest have recovered.