"If the departure places are not at high risk of the pandemic, it is possible," Professor Yik Ying Teo, dean of the Saw Swee Hock School of Public Health, National University of Singapore, told VnExpress International while speaking about factors that Vietnam should consider to apply shorter quarantines.

The Centers for Disease Control and Prevention on Wednesday announced two shortened alternatives to its recommended 14-day quarantine for people who were exposed to Covid-19.

One alternative is to end quarantine after 10 days if no symptoms are reported. The second option is to end quarantine after seven days if the person tests negative and shows no symptoms.

Vietnam currently allows flight crews short-term quarantines to ensure staff availability. Businesspeople and experts coming into the country can also leave centralized quarantine after five days, but have to isolate themselves at home or their workplace.

Such eased forms of quarantine are part of the government's efforts to maintain a balance between pandemic prevention and economic operations.

A government quarantine zone in District 3, HCMC.
Photo by VnExpress/Quynh Tran.

Experts said quarantine policy could be flexible and more relaxed for people coming from safe destinations.

Teo said Singapore does not quarantine people coming from safe countries like Brunei and New Zealand, merely tests them on arrival, but those coming from some other places are quarantined for at least seven days.

"For very high-risk countries, the government requires a 14-day quarantine."

But he was unhappy with the five-day quarantine being considered in some nations, saying the incubation period is 14 days. There is also the risk that one in 20 people continue to develop symptoms after 14 days, meaning that even a 14-day quarantine is not 100 percent safe, he said.

Citing another factor for considering a shorter quarantine period, Professor Hitoshi Oshitani of the department of virology at Tohoku University Graduate School of Medicine, Japan, said there is a debate in his country about shortening the quarantine period since most infections are occurring within seven days.

The reduction depends on other measures being implemented, including monitoring of symptoms after a short quarantine and contact tracing, he said. Japan is using smartphones to monitor people's health in some places, asking them to report possible symptoms, he said.

Authorities and experts are studying data on incoming passengers for possible symptoms and transmission to decide on a shorter quarantine, he said.

"We are going to do some studies to understand the transmission pattern of these people. We have not discussed any details yet, whether it should be five days, seven days, or 10 days."

Japan still has a 14-day mandatory quarantine and he said that might not be reduced soon.

For Teo, the quarantine question was not just about how long but also where.

Quarantining people at home is extremely risky since the person could go out and other people could stay in close vicinity, and there is a very high chance it would be transmitted within the household, he said.

"For that reason, quarantining travelers coming from high-risk countries in a government facility will still be the best option."

But it is up to individual countries to decide whether having a few community cases because of leakages from home quarantine is acceptable in return for the economy and aviation returning to normal.

Professor Michael Baker of the public health, faculty at the University of Otago, New Zealand, said preventing community transmission would continue to be a challenge for Vietnam, mainland China, Taiwan, Australia, and New Zealand, which are pursuing a strategy of balancing between Covid-19 prevention and maintaining economic activities.

The threats include the increasing global intensity of the pandemic and public fatigue and complacency with control measures, he said.

Nevertheless, the fact that effective vaccines would be available in the medium term is an important reminder that control measures would not be required forever and there is an end in sight, he added.

Oshitani said it is quite difficult to implement aggressive measures for a long time when people are getting tired of them, and Japan is still discussing how to balance social and economic activities with suppression of the virus.

"This is quite a big challenge for every country."

Teo said the risk remains high for countries like Singapore and Vietnam that have had some success in containing the virus, and primarily from travelers entering the country with the infection.

But public health measures including contact tracing in Vietnam are being implemented well, he said.

"Vietnam might have some people getting in the second generation or the third generation spread but I don't actually anticipate that it will result in a huge wave."

With the spread of the infection by the flight attendant to three other people, the country’s Covid-19 tally has risen to 1,361. The disease has claimed 35 lives.