Coronavirus: Singapore

S'pore reining in virus, but don't let guard down yet, say experts

Local cases tapering off but imported infections could still seep into community

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People dining at Prinsep Place last Friday night while practising safe distancing measures. Since Nov 1, there have been fewer locally transmitted cases, with two from the community and five from the dorms on Nov 3, 4, 5 and 10. Most cases have been

People dining at Prinsep Place last Friday night while practising safe distancing measures. Since Nov 1, there have been fewer locally transmitted cases, with two from the community and five from the dorms on Nov 3, 4, 5 and 10. Most cases have been imported, with the highest daily number being 18 on Nov 11.

ST PHOTO: DESMOND WEE

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For the past 13 days, there has been zero Covid-19 cases from the dormitories and the community, marking the longest stretch without local cases in Singapore since the pandemic started.
Although infectious disease experts say this indicates Singapore's success in containing the virus amid soaring and resurging cases abroad, they stress that it is not time to get complacent as Covid-19 is not over in the country.
Since Nov 1, there have been fewer locally transmitted cases, with two from the community and five from the dorms on Nov 3, 4, 5 and 10.
Although local cases seem to be tapering off, the experts cautioned that local cases may still be lurking.
"Getting zero cases does not mean we have reached zero infections," said Associate Professor Alex Cook, vice-dean of research at the National University of Singapore's Saw Swee Hock School of Public Health.
The school's dean, Professor Teo Yik Ying, added: "There could still be a very small number of undetected asymptomatic or mildly symptomatic cases that are circulating, and may seed further community cases.
"Unless there is widespread and routine testing like what we do for migrant workers in dormitories, it will be difficult to identify asymptomatic cases in the community."
Also, with imported cases trailing in each day, the chances of imported infections seeping into the community still exist, said the experts. Since Nov 1, the country has mostly seen imported cases in single digits daily, with the highest being 18 on Nov 11.
"Even with 14 days of strict quarantine and an exit test, a small percentage of infected travellers will pass undetected. That is why I don't get too excited about reaching zero cases - there is always a risk of spillover from importations," said Prof Cook.
Some who get infected shortly before flying into Singapore will have a long incubation or latent period before the virus manifests itself, and that causes them to test negative on their exit swab at the end of their quarantine, he added.
"Most imported cases will be detected, either manifesting symptoms while in quarantine or testing positive at exit, but a small fraction will not be," Prof Cook said.
The experts also said imported cases may rise during the festive seasons between next month and February, and as more students studying abroad return home during the winter break.
But the chances of them spreading Covid-19 to the community are slim as Singapore frequently updates its border control measures and stay-home notice (SHN) policies based on changes in the coronavirus situation abroad.
From this month, all travellers from Estonia, Norway, Malaysia and Japan must serve their 14-day SHN at dedicated facilities owing to a resurgence of cases in these countries. Previously, eligible travellers could complete their SHN in their homes, while travellers from Malaysia, except Sabah, could serve their seven-day SHN in their homes.
At the dorms, experts attribute the turnaround of cases to measures such as fortnightly testing of the migrant workers to ring fence cases, movement restrictions and reducing the density of workers in each dorm.
"The longer that comprehensive disease surveillance is conducted without detecting new cases, the more likely that this means a reduction in cryptic cases in the dorms," said Professor Gavin Smith, interim director of the Emerging Infectious Diseases Programme at Duke-NUS Medical School.
With no cases in the community or dorms for nearly two weeks, what is Singapore's current target in controlling Covid-19?
"Singapore's spell of zero community cases shows it is not a pipe dream, but attainable and sustainable," said Prof Teo.
But maintaining zero cases must be balanced with economic growth and safe resumption of social activities, experts said.
"Zero cases is fantastic, but we should not have zero tolerance for cases," said Professor Dale Fisher of the NUS Yong Loo Lin School of Medicine.
"Singapore is leading the way in nuancing its border restrictions to lessen the social and economic impacts, and I think the health risks are very small and manageable."
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