Nguyen Viet Nhung, director of the National Lung Hospital, said quarantining people in government facilities has enabled Vietnam to efficiently contain the spread of the diseases.

"But with a large number of people in quarantine now, it poses a risk to those facilities, threatens to overload them and imposes a burden on the government in terms of human and financial resources."

Protocols require also those returning from abroad and, in some cases, Covid-hit areas to be quarantined, and since early May authorities have extended the quarantine period from 14 to 21 days.

People in quarantine need to pay VND80,000 ($3.48) a day for food, with exemption for poor people.

Data from the Ministry of Health shows that as of Tuesday 20,209 are in quarantine facilities and 151,127 others are self-quarantined at home and elsewhere.

Most of the former are in the nation's three biggest hotspots Bac Giang and Bac Ninh provinces in the north and HCMC. Given the large number, Nhung raised concerns about cross infection.

"Those who did get the virus from a Covid-19 patient could possibly end up getting infected in quarantine," he pointed out.

Nguyen Huy Nga, former director of the ministry's preventive medicine department, concurred.

He said the latest outbreaks in Vietnam are caused by the U.K. and Indian coronavirus strains that are more transmissible than earlier ones, resulting in a lot of infections in a short period of time and putting large numbers of people in quarantine.

"If Vietnam is to continue with the protocol of quarantining everyone who came into direct contact with Covid patients, it will lead to overload and there is no guarantee that cross infection will not occur."

Tran Dac Phu, a senior advisor to the Public Health Emergency Operations Center, said, "The current pandemic situation is different than before, the number of people in quarantine camps is too high, and there are risks."

In the six weeks after the latest Covid wave began, there have been more than 6,537 infections as of Thursday noon. Since the pandemic broke out last year, there have been only 9,635 cases, over 1,600 of them imported.

With the number rising steadily in HCMC, district authorities have expressed concern about not having enough space to quarantine people coming into contact with patients, prompting the city to add a college dormitory and a military training school to the list of quarantine facilities on Tuesday.

But experts are suggesting instead that people meeting certain conditions should now be allowed to quarantine themselves at home.

Nhung said, "Both medics and members of the public are well aware of what needs to be done to contain the Covid-19 spread and health authorities should let people who had direct contact with patients to choose if they want to quarantine themselves at home."

Those who prove they could isolate themselves completely from others should be allowed to self-quarantine and only those unable to meet the requirement should be sent to government facilities, he said. Medics should be trained to make this call, he said.

He suggested setting up CCTV cameras or using tracking wristbands to monitor people isolating themselves, and said anyone breaching the rules should face criminal charges.

Nga said, "Self-quarantining will also contribute to economic development because it would allow people to continue working from home, which they might not be able to in centralized camps."

Having fewer people in quarantine would ease the burden on the government's human and financial resources too, he pointed out.

Besides, remaining at home would make quarantine less stressful for people, he said. He too suggested the use of surveillance technologies to eliminate risks related to people self-quarantining.

Phu suggested categorizing people into two groups, high-risk and low-risk, and send only the former to government quarantine.

The high-risk group would comprise those who stayed in close proximity to a Covid patient in closed, air-conditioned places without masks, while the low-risk people would have kept a distance, worn masks and met patients outdoors, he said.

But the self-quarantining option should only be allowed in areas where government facilities are overloaded, and medical personnel should be trained well to make this decision, he said.

The ministry has already permitted Bac Giang and Bac Ninh provinces to trial self-quarantining of people who were in close contact with patients.