SINGAPORE - Asian countries such as South Korea, Vietnam and Singapore are doing well in their fight against Covid-19, said a World Health Organisation (WHO) adviser as he praised their efforts to build hospital capacity, perform contact tracing and isolate patients.

"You've been prepared after the Mers (Middle East respiratory syndrome) or the Sars (severe acute respiratory syndrome) corona outbreaks that have occurred in the past years," said Professor David Heymann, who chairs the independent Strategic and Technical Advisory Group for Infectious Hazards, comprising international experts, that advises WHO.

"You've developed the capacity you need in your hospitals to deal with a surge. You've also been able to do contact tracing and isolation of patients, which many countries in the rest of the world abandoned very early.

"The best examples are what's going on in Singapore, in Hong Kong, in Taiwan and South Korea and in Vietnam. You've been able to keep the reproductive number low, you've been using these unique 'circuit breakers' instead of just locking down everything at once.

"You've locked down parts of the economy, and then opened it up again," said Prof Heymann during a panel discussion hosted by The Straits Times on Friday (May 29).

Singapore's circuit breaker measures will be eased in three phases from June 2 onwards.

About 75 per cent of the economy can resume operations in Phase 1, from June 2.

The second phase will see almost the entire economy resuming operations and this could happen some time before the end of June, National Development Minister Lawrence Wong said on Thursday (May 28).

Earlier this month, selected businesses such as hairdressers and pet supply stores had been allowed to raise their shutters, subject to certain restrictions.

Prof Heymann, an infectious disease epidemiologist at the London School of Hygiene and Tropical Medicine, said it makes sense to open up the economy in stages.

"We have to learn to live with this disease while it's with us, and the best way to do that is to begin to cautiously - with the systems of monitoring in place - open up schools, open up businesses and get on with life, as is happening now in Europe."

More than 33,000 people in Singapore have been infected with the coronavirus. Hundreds of new cases - mostly low-wage migrant workers living in dormitories - are reported daily.

While Singapore was praised for the way it handled the coronavirus epidemic in the initial days, the subsequent surge in infections in crowded migrant worker dormitories has sparked criticism from rights groups and other observers - with people calling on the authorities to improve the workers' living conditions.

The other Asian economies mentioned by Prof Heymann have reported a far lower number of infections. Vietnam and Taiwan, for example, have seen just hundreds of infections.

South Korea, which has more than 11,300 Covid cases, has re-imposed a series of social distancing measures which had been eased previously.

This came as officials announced 79 new cases on Thursday - the country's biggest spike in new infections since 81 new cases were announced on April 5.

Also on the discussion panel on Friday was Professor Teo Yik Ying, dean of the National University of Singapore's Saw Swee Hock School of Public Health.

Asked where could be the most likely places of transmission of the disease when the circuit breaker eases, he suggested that the risk level of an activity depends on whether people take the necessary precautions.

"Nobody can guarantee that when we ease some of these restrictive measures, there will not be a resurgence. What we do know, based on data from Singapore and the rest of the world, is that the coronavirus spreads best when people are interacting in fairly close proximity, perhaps over an extended time, be it talking or eating together.

"This is why many sensible governments worldwide, as well as the WHO, issued the same reminders around safe social distancing, to minimise physical interactions, good personal hygiene, and advice on mask-wearing."

Asked if the coronavirus could survive in swimming pools, Prof Heymann said there have been no outbreaks associated with swimming pools so far.

Fellow panellist and National Centre for Infectious Diseases' executive director Leo Yee Sin said: "But don't forget, we are not going to be in the water all the time. We are going to get up, we're going to go to the toilet...

"If you go to the toilet, how do you use the facilities? Is it going to be crowded?"