SINGAPORE: New COVID-19 cases found at the migrant worker dormitories are a result of routine testing, and these cases are surfacing as “part of the plan”, said Manpower Minister Josephine Teo on Wednesday (Aug 26).
“We have planned for every single one in the construction, marine and process sector, as well as the people who come into close contact with them, to be regularly tested. So, the findings today are a result of those testing,” Mrs Teo said.
“That is what we are doing, it is part of the plan and it is surfacing as part of the plan.”
Speaking to the media after visiting a US medical technology firm on Wednesday, Mrs Teo said: “If we had not implemented rostered routine testing, it doesn't mean that the cases don't exist - it just means that we don't know about it.”
However with the testing, clusters can be identified early, infected workers can be given appropriate care and their close contacts can be quarantined to contain the spread, she said.
COVID-19 cases among migrant workers in dormitories have formed the bulk of more than 56,000 infections in Singapore. Authorities took about four months to test all workers, more than 300,00 of them.
The testing was completed on Aug 7, and the Ministry of Manpower (MOM) declared all dormitories “cleared of COVID-19” on Aug 19 but urged continued vigilance.
This was partly because even before Aug 19, about 100 new cases of COVID-19 were detected in dormitories that were previously given the all clear from the virus.
A few new clusters have been found at other “cleared” dormitories since, including a cluster of more than 60 at Sungei Tengah Lodge, Singapore's largest purpose-built dormitory. Around 4,800 workers were issued stay-home notices at the dorm along Old Choa Chu Kang Road.
READ: COVID-19 cases detected again in cleared migrant worker dorms, about 7,000 quarantined due to new infections
Infectious diseases experts told CNA that there are several reasons why dormitories “cleared” of COVID-19 would still see new cases and clusters.
“It’s important to be clear what ‘clearing’ means,” said Associate Professor Alex Cook, vice-dean of research at the National University of Singapore’s Saw Swee Hock School of Public Health.
“At the point at which the clearing of any particular dorm was done, there were no remaining infections that we had identified. That does not mean that there were no infections.”
For example, a person could have been infected a day or two before the clearance exercise, and still test negative for the virus.
“Even though the vast majority of ‘cleared’ residents were not infected, some infected residents will have been allowed out, where they may have come into contact with workers living in other dorms or in the community,” he said.
“We try to pick these up through report-sick operations and repeat testing of residents but it would be far too expensive to do daily testing, so some will be missed, and outbreaks can grow,” said Assoc Prof Cook.
READ: 51 new COVID-19 cases in Singapore; new cluster found at dormitory that was previously cleared of the disease
Infectious diseases expert Dr Piotr Chlebicki told CNA that because workers in the dormitories are young, healthy men, many of them don't display any symptoms when infected.
"These people don't have large amounts of the virus ... and it's easy to kind of miss it from time to time. If one sneaks through, then everything starts all over again," said Dr Chlebicki, who runs the Infectious Diseases Medical Clinic at Mount Alvernia Hospital.
MOM said that it is trying to prevent a second wave of infection in the dormitories through prevention, detection, containment and isolation.
Migrant workers staying in the dormitories are “cohorted” by the type of industry that they work in and safe distancing measures have been implemented there. They need to undergo the rostered routine testing every 14 days.
READ: Travellers to Singapore with recent travel history to South Korea to serve stay-home notice at dedicated facilities
While the Health Ministry and MOM have been proactive in preventing new clusters, there are limits to this, said Associate Professor Josip Car, director of the Centre of Population Health Sciences at the Nanyang Technological University’s Lee Kong Chian School of Medicine.
But he added that the circumstances are now very different from when cases in the dormitories first spiked in April.
“Now that worker dormitories are more spread out, with clearer demarcation between the presently healthy and the infected, we should be better placed to trace and isolate the transmission spread to mitigate any potential unlinked transmission cases,” he said.
“We learn every day how to better detect virus, how it spreads, how to manage the infection. We now have a wide range of measures in place, including in dormitories, which make it more difficult for the virus to spread."
Assoc Prof Cook said that unless there is population immunity among the workers at the dormitories, there will always be the risk of more infections, but there will not be an “explosive spread” as before.
“It is clear from the recrudescence of these outbreaks that herd immunity has not been reached in at least some dorms, 15 to 20 per cent of the residents have been identified to be infected through swabs to date, which is far too low to confer herd immunity on them,” he said.
“Fortunately though even if the dorms, or an affected dorm, haven’t reached herd immunity, the fact that some residents have been infected already will prevent explosive spread like we saw in April.”
Assoc Prof Car warned that people should not “drop their guard” and advised that social distancing remains “paramount”.
“Phase 2 has been happening for a while and it feels like some normality is returning in terms of normal social behaviour, but if anything, we should not reduce our own individual vigilance. This isn't a migrant-or-locals issue. COVID-19 doesn't look at one's passport.”
Singapore reported 60 new COVID-19 cases on Wednesday, taking the cumulative total to 56,495. As of Tuesday, there were 78 patients still in hospital and 1,514 cases are isolated and cared for in community facilities.
Additional reporting by Tang See Kit.