SINGAPORE: More imported cases of COVID-19 have been detected among people entering Singapore in recent weeks, with the daily number hitting 48 on Sunday (Jan 24).
This matches the one-day high in the first wave of imported cases last year, when 48 imported cases were reported on Mar 23, 2020. All short-term visitors were barred from entering or transiting through Singapore from 11.59pm that day.
After that, the number of imported cases fell over the next two weeks to nearly none, and this continued during the "circuit breaker" period in April and May, and through June.
From July, the number of imported cases started climbing but it was usually in the single digits each day, reaching 15 or 18 cases on some days. The number began to inch up around mid-December, and in January, it ranged between 10 and 48 per day.
READ: Demand for new maids high despite extra costs amid COVID-19 restrictions, risk of imported cases
Education Minister and co-chair of the COVID-19 task force Lawrence Wong said on Monday that the increase in imported cases is not due to "a large volume of people" coming into Singapore, and that the two largest groups entering the country are construction workers and foreign domestic workers.
"Those are the two largest sources of travellers coming to Singapore, and the daily numbers have not increased, they've been about the same in recent times," he said in a dialogue session at the Singapore Perspectives Conference 2021.
"Why have the numbers gone up? It's simply because the prevalence rate, the incidence rate of the disease is much higher. Now, the virus is raging in countries everywhere."
STRONG QUARANTINE MEASURES
Experts said Singapore does have strong quarantine measures to keep imported cases from spreading locally.
"In that regard, I don’t find the rise in the number of imported cases to be extremely concerning. We have quite strong quarantine measures in place, which blocks off most of the risk of spread to the resident population," said Associate Professor Alex Cook, vice dean of research at the National University of Singapore's Saw Swee Hock School of Public Health.
For visitors from most countries and territories, they have to serve a 14-day stay-home notice at a dedicated facility and take a COVID-19 test on arrival as well as at the end of their stay-home notice.
They need a valid reason to enter, so they have to be a returning Singaporean or permanent resident, their family members, a student pass holder or a work pass holder.
Measures have also recently been tightened for arrivals from some countries, with a 21-day isolation period for anyone travelling from the UK or South Africa. In addition, COVID-19 antigen rapid testing has been rolled out for cargo drivers entering Singapore from Malaysia via land checkpoints.
However, visitors from a number of countries with low COVID-19 infection rates, including mainland China, Vietnam, New Zealand and most parts of Australia, are exempt from stay-home notice requirements. Short-term visitors are also allowed if they apply for an Air Travel Pass.
It is "safe and sensible" to allow travellers from countries and territories with a low number of COVID-19 cases to enter with short or no quarantine periods, said infectious diseases expert Professor Dale Fisher.
"The capacity to quarantine travellers is a finite resource and we should not waste them on travellers from countries with no or virtually no COVID. That traveller is exceptionally low risk," said Prof Fisher of the Yong Loo Lin School of Medicine at the National University of Singapore.
READ: COVID-19: What is preventing countries lifting border restrictions to travellers from Singapore?
READ: Away from their families, Malaysians in Singapore brace themselves for a quiet Chinese New Year
HALF OF RECENT IMPORTED CASES FROM INDIA, INDONESIA
As of Wednesday, there have been a total of 2,568 imported COVID-19 cases in Singapore, of which 2,276 cases were isolated before they tested positive.
According to figures tabulated by CNA, there have been nearly 1,500 imported cases since Oct 1. Among these, arrivals from India and Indonesia make up about half of the cases, and there have been about 100 cases from Bangladesh and 92 cases from Myanmar.
To put things into perspective, the number of arrivals in Singapore was 14,676 in November, a slight uptick from October's 13,397 visitors. Numbers for December are not publicly available yet.
The chart below from the Ministry of Health's (MOH) situation report on Jan 25 shows the steeper climb in the number of COVID-19 cases relative to arrivals from around December.
For November, travellers from China made up the largest group of arrivals with 4,007 visitors. Indonesia came next with 3,121 people coming to Singapore, followed by Malaysia. Travellers from India made up the seventh-largest group with 500 people that month.
Mr Wong explained on Monday that while people entering Singapore take a pre-departure COVID-19 test, these are not "foolproof" as they could be incubating the virus. This is why the majority are put on stay-home notice on arrival.
"We will continue to take (these precautions) to ensure that even as we have a continued flow of people coming in - which is needed for Singapore, economy and society to function - we ... isolate these cases from seeping through our community," he said.
"NOTHING IS WATERTIGHT"
Experts noted some places where the virus can enter the Singapore community, such as the airport and places of quarantine, where there are many people involved in managing arriving travellers.
"Nothing is watertight and attention to infection prevention protocols by the travellers and managers of the quarantine hotel and its workers are critical," Prof Fisher said.
"In other countries, we have seen new clusters after no COVID for even 100 days, so we know border infection control breaches happen on occasion."
Assoc Prof Cook said that even so, there is no need for border controls to be completely impervious.
"The measures we have in place to prevent transmission in the community should suffice to mop up infections that break through the cordon," he said.
However, he is concerned that more transmissible variants, such as those first reported by the United Kingdom and South Africa, are establishing themselves here. The variants have been reported to be 30 to 70 per cent more contagious.
"It has just been reported that some of the community cases earlier this month had the B117 strain, so the risk is real, though the numbers are still quite small," he said.
"As this virus is more transmissible, there are more opportunities for secondary cases, and in turn a greater potential for it to become established in the community and jeopardise the success of our safe management measures."
The Health Ministry has been monitoring different strains of the virus over the past year as it mutates, said the Director of Communicable Diseases Associate Professor Vernon Lee on Monday, who spoke to the media at on the sidelines of an event to show how MOH contact tracers work.
"The approach to dealing with all of these strains is similar: We detect cases, as soon as possible. We ringfence them through contact tracing, and of course, testing, quarantine ... If we contain them, it doesn't spread, then that's a dead end, and it doesn’t matter what strain it is."
To make sure that imported cases don't blow up into local clusters, it's still important to keep to safe distancing measures, and also to get vaccinated when that is available, both experts said.
READ: COVID-19: Patients with mild symptoms may hesitate to see a doctor; experts urge public to be vigilant
"Lately, a lot of the cases we’ve identified in the community had symptoms but delayed getting diagnosed ... for most of us, the biggest thing we can do apart from getting vaccinated, adhering to mask-wearing and social distancing is to be alert to your own symptoms," said Assoc Prof Cook.
"Don’t let symptoms of a cold or flu last more than a day or two before going to the doctor to get swabbed, just in case it’s actually COVID-19. The same sensitivity to symptoms should be encouraged in any travellers."
HOLDING LARGE EVENTS
As Singapore prepares to host larger events involving overseas visitors, current measures will have a big part to play in reducing the risk of possible transmission.
The country is due to host the Special Annual Meeting of the World Economic Forum in May, and the Shangri-La Dialogue will resume this year.
Prof Fisher said the risk of large gatherings is that they can become "superspreading events".
To avoid that, one must first prevent infectious individuals from participating in the event. Should a COVID-19 case slip through, measures must be in place to minimise the impact on others.
"This will mean keeping groups small, minimising mingling between groups, ensuring safe distancing and mask-wearing. All our tools will have a role, including vaccination and testing," he added.
Frequent testing would be essential to nip any transmission chains in the bud, said Assoc Prof Cook. Testing at the border and controlling the itinerary of visitors would also reduce the risk of these events spilling over into the community, he added.
"I am confident that the events will be well organised to reduce this risk. After all, Singapore will be keen to demonstrate to the world that we can handle such large events safely," he said.