It has been a month since the circuit breaker measures kicked in.

While the total number of infections remains high, the number of new cases in the community has been coming down, raising hopes that the virus has been, if not beaten, at least brought under control. Many have started looking forward to a semblance of normal life.

In an ideal world, Singapore will see no new cases for a fortnight, given that the virus incubation can stretch to as long as 14 days, and return to normalcy.

But given that there are still 20 to 30 new cases in the community every day, not to mention the hundreds among dormitory workers - who have essentially been ringfenced - this could take a long time.

Should Singapore wait for this perfect scenario before it relaxes the circuit breaker measures?

Probably not, because even this scenario would not guarantee that we are truly free of the virus.

Since some people infected with Covid-19 show few or no symptoms but can still infect others, no new cases could merely mean undetected cases.

Putting businesses on hold and making the entire nation wait for this may be extreme.

But as the multi-ministry task force has said many times, opening up has to be done gradually in a controlled manner - and not in one big bang, as that could see infections return with a vengeance.

Professor Teo Yik Ying, dean of the NUS Saw Swee Hock School of Public Health, expects telecommuting to continue, as well as the wearing of face masks when out and safe distancing when the current measures are eased.

"I don't anticipate dining-in at hawker centres, foodcourts or restaurants will resume that quickly," he said. "So the opportunity for community transmission is actually going to be lower."

RESURGENCE

But he and other experts do expect to see more new cases emerging once measures are relaxed, even with people taking precautions, as there are unknown virus carriers in the population.

Also, without herd immunity, the vast majority of the population remains susceptible to being infected by the virus.

This is why the country cannot totally relax all measures.

Said Prof Teo: "We should see the situation stabilise. I do not expect (the infections) will go up in a dramatic way. Likely we will return to the situation in February or early March, with single-digit new cases per day."

Associate Professor Hsu Li Yang, an infectious diseases expert and an epidemiologist at the school, agreed that with limited interaction, "it is very unlikely that there will be an explosion of cases".

However, Associate Professor Alex Cook, vice-dean of research at the school, said international models suggest the need for repeated waves of lockdowns with resurgence of infections once the measures are eased.

"Starting the circuit breaker again would be painful, but it is reassuring to know that we can expect it to work should ever the spread threaten to overwhelm the health system," he said.

TESTING

Experts were divided on the benefits of testing the entire population to find out if people are, or had previously been, infected.

Prof Teo said serology tests, to find out how many had already been infected unknowingly, will give policymakers an idea of how susceptible the population is, and help them plan.

But Prof Hsu cautioned that if widespread serology testing is carried out, the Government has to carefully consider whether a positive test result means the person can then be allowed to go about freely.

This is because there will always be "a small percentage who test positive, but will not actually have had the infection before". But they may then get a false sense of security and behave in a way that increases their risk of a real infection, he said.

The choice of tests is also important, he added, as some have low levels of accuracy.

"Many of the early serology tests, particularly the rapid finger-prick tests, should never have been licensed or sold," said Prof Hsu.

And there are still a number of unknowns, including whether people who have been infected become immune to re-infection. It seems that such re-infection and transmission appear possible.

Also, most serology tests simply indicate the presence of antibodies. But little is known of the level of response the body needs to prevent a future infection.

To test the entire population could cost hundreds of millions of dollars.

Tests to check if people are currently infected are accurate, Prof Hsu said, but added: "Nasopharyngeal swabs are labour-intensive and result in pain and discomfort (in people being tested)."

Prof Cook said for now, priority for such tests should be given to those who show symptoms, until there are "plentiful tests" for the population.

So far, Singapore has conducted more than 140,000 such tests. It is ramping up testing capabilities to 40,000 a day by next month - from the current 8,000 a day.

Prof Teo added: "In an ideal world, everyone in Singapore is tested once a day for active infection, which will allow anyone who is infected to be isolated and contact tracing can proceed to quarantine the majority of the contacts."

People need to be tested more than once, as those who test negative may have the virus, but show no signs because it is still incubating.

"In the real world, we are unable to achieve that degree of testing," said Prof Teo. Instead, he advocates "having clever strategies" to actively test groups of people at higher risk, or who may pose a risk for the vulnerable.

Singapore is doing that.

Health Minister Gan Kim Yong said in Parliament on Monday: "We have started to test staff and residents at Ministry of Health and Ministry of Social and Family Development homes with a high proportion of seniors, such as nursing homes and welfare homes."

Infections have occurred at seven such homes, with more than 35 residents and staff diagnosed with Covid-19. Some of them have died.

TRAVEL

Once measures here are relaxed, should Singapore open its doors to travel again?

Prof Cook said he would be surprised if the strict 14-day quarantine for people entering Singapore is abandoned in the near future as it was "leakage from home quarantine that led to the elevated cases before we went into circuit breaker".

But if the quarantine protocol is maintained, then there is no harm in letting people in, he said. "This would allow students to enter or leave Singapore with minimal risk to society, or allow people to attend important events, but probably prevent most tourism."

Prof Teo, on the other hand, expects some easing of travel restrictions, but only with certain countries.

He said: "Some countries may come together to form 'travel bubbles', where travel may be less restrictive, but travelling to countries outside the travel bubbles may include additional quarantine either way, perhaps complemented with testing."

But he, too, does not foresee unrestricted global travel any time soon.

Prof Hsu also thinks many countries "will open up a limited number of borders at a time" with vital partners or with countries where the spread of Covid-19 is contained.

He said: "There is a lot of interest and thought about 'immunity passports' for the purposes of work and cross-border travel, including testing before travel and/or on arrival."

But opening up travel will carry the risk of importing the virus - as had happened at the start of the year.

But so long as the numbers remain low and people adhere to safety measures, it is unlikely to lead to an explosion of cases.

But as Prof Cook said, should the numbers go up again, circuit breaker measures can be re-implemented for a period.

As long as the healthcare system is not overwhelmed and vulnerable seniors are protected, it would be good to return to a more normal life.

The new normal will be different from what was normal in pre-Covid-19 days.

Until a vaccine becomes available and can be administered to the masses, masks, safe distancing and an absence of large gatherings are here to stay.

Meanwhile, whether Singapore will need another round of circuit breaker measures will depend on how cooperative everyone is.

A minority behaving irresponsibly could see Singapore needing an even tighter lockdown.