Experts in Singapore wary of rise in mutant coronavirus strains amid plans to relaunch Hong Kong travel bubble

Singapore is facing an uptick in Covid-19 cases amid reports of a rising number of mutant strains circulating overseas, with health care experts saying this trend should be closely watched as the city state seeks to launch a quarantine-free travel bubble with Hong Kong.

Health authorities on Monday (April 20) afternoon reported 20 new infections, 19 of which were imported. Of the island nation’s 170 imported cases in the past week, 63 came from India, which is battling a deadly new wave of cases stemming from a new and possibly more virulent variant of the disease.

While Singapore has largely brought the virus under control, in recent months it has reported between 10 and 40 imported cases a day as foreigners with work passes and student passes return to the country, along with those on dependent passes.

Those arriving from overseas are typically required to quarantine at a government-designated facility or hotel for two weeks, and need to test negative for Covid-19 before they are allowed to roam freely in the Southeast Asian nation.

According to the health ministry, travellers entering from Britain and South Africa are required to serve an additional seven-day stay-home notice after the initial quarantine period.

The single locally transmitted case reported on Monday brought the tally for this month to 13, compared with nine locally transmitted cases for the whole of March.

However, experts pointed to the detection of two new local infection clusters in the past week as a sign residents should not let their guard down. 

One of them involved an Indian national who experienced the onset of Covid-19 symptoms on April 12 when he reported to work at the National University of Singapore, after completing his quarantine obligations following a trip to India from Dec 28 to March 21.

He had tested negative three times during quarantine.

At the centre of the other cluster was a 50-year-old Colombian national who came to Singapore from Papua New Guinea for a project but tested positive on March 30. Four other people, including those on his flight and from his workplace, were later confirmed to be infected.


Jeremy Lim, an associate professor at the National University of Singapore (NUS)’s Saw Swee Hock School of Public Health, noted that the recent clusters involved imported cases that had slipped through Singapore’s Covid-19 restrictions.

But whether authorities decided to tighten measures again, he said, would hinge on several factors – including the health care system’s capacity to test, isolate and contract trace, as well as the pressure the new cases placed on hospital and ICU bed capacity.

“We all recognise that there are trade-offs balancing economic activity, mental health, and social interactions with pandemic control measures,” Lim said. “I’m sure the government is tracking multiple data points to aid decision making and will not hesitate to tighten measures as needed, even as we now focus on restoring some degree of economic activity and address societal and mental health consequences of the pandemic.”

Infectious diseases expert Leong Hoe Nam said he was particularly concerned about the recent spike, and suggested that while Singapore’s strategy to weed out Covid-19 had been stagnant, the virus was rapidly evolving.

“It is constantly mutating and adapting … and is trying to circumvent our pandemic measures,” he said, adding that the country’s vaccination roll-out should continue, with improvements to contact tracing, as there could be further outbreaks.

According to figures from the health ministry, close to 20 per cent of Singapore’s population of 5.7 million had received at least one dose of the vaccine as of April 6.


Leong added that imported cases could be worrying given reports of a growing number of mutant coronavirus strains around the world, from countries such as Britain, South Africa, Brazil, and most recently India.

One of Singapore’s positive cases on Sunday reportedly returned a preliminary positive result for the British variant of Covid-19, 25 cases of which were detected in the island nation this January.

Leong said there was a possibility the other variants had also made their way to the country, but he said the authorities should be able to identify them early, either at the immigration or quarantine centres.

“It is not if, but when, [these strains arrive]. In fact, I would put my last dollar down that the E484K mutants have arrived at our doorstep, but we have not tested them yet,” he said, referring to the strains found in South Africa and Brazil.

Leong also expects the number of imported cases to surge up to 80 per day going forward, noting that mutant variants cause patients to fall sick multiple times.

Lim from NUS said Singapore had to expect the presence of mutant strains as it continued to progressively open up its borders, adding that vigilance was key to stamping out these new variants: “We should be concerned but not paranoid, cautious but not paralysed by fear or indecision.”


As the virus situation remained dynamic around the world, he said eleventh-hour changes to the Singapore-Hong Kong travel bubble should be expected. Details of the much-anticipated travel corridor, which stalled last year due to a spike in infections in the latter city, are set to be announced soon. 

Lim said the bubble remained an important business initiative, but its timing would be dependent on the likes of the Covid-19 caseload, the velocity of new infections, and the capacity of the health care system on both sides. 

Meanwhile, as the number of coronavirus infections in Asia continued to swell, Hong Kong on Sunday announced that it would impose a two-week travel ban on arrivals from India, Pakistan, and the Philippines after authorities in the city deemed the three countries as being “extremely high risk”.

This article was first published in South China Morning Post.