Until an effective vaccine is rolled out, distancing, isolation and quarantine may be the only effective tools for containing the spread of Covid-19. But these measures can range from the sharply focussed to the very blunt.

When it comes to Covid-19 risks among dormitory-resident migrant workers, Singapore seems to have chosen the bluntest possible approach, resulting in great cost to our economy. Why we have chosen this approach is open to debate, but our sense is that it largely comes out of structural constraints, namely, the density in which we continue to house migrant workers. Our conservatism may also have something to do with it — unable to think outside the box, relying only on tried and tested ways.

Part of Sungei Tengah Lodge locked down again

The bluntness of our approach can be seen from the recent news that 4,800 workers at Sungei Tengah Lodge have been issued Stay-Home Notices (isolation orders) after 175 cases of Covid-19 were found in a new cluster at the dormitory (ChannelNews Asia, 28 August 2020, New COVID-19 cluster at Singapore’s biggest dormitory that was previously cleared grows to 175 cases)

This incident suggests a ratio of 30 workers immobilised for every new case found. Employers hoping to resume work with those workers now have their plans scrambled.

Sungei Tengah Lodge is Singapore’s largest purpose-built dorm capable of housing 25,000 workers. It was placed under quarantine from 9 April 2020 to 18 July 2020 – more than three months – because of an earlier outbreak which eventually totalled over 2,200 cases. Just five weeks after the dorm was declared “cleared” of the virus, the latest cluster was found on 22 August and thousands of residents were locked down again.

This dorm is not the only one seeing a resurgence of cases after being cleared. New clusters have also been found in Homestay Lodge in Kaki Bukit (seven cases as at 30 August) and Tuas View Dormitory (six cases as at 30 August).

Exactly how these new clusters were seeded remains unknown. They raise questions, however, about the reliability of testing, despite the fact that all the dorm residents had previously been tested and cleared. Especially as inhumanly strict movement controls are still applied to workers allowing them only to go out to work using company transport, it cannot be likely that they were infected through contact with the general public.

Indeed, one may wonder if the extremely strict movement restrictions, requiring workers to stay amongst the same group of co-workers all the time whether at work or at the dorm, contributed to the rapid spread of these new clusters. By compelling workers to stay in close proximity with the same other workers all the time, we may be intensifying mutual contact and resulting transmission.

Perhaps we should entertain the counter-intuitive possibility that letting them out might reduce transmission more than locking them in.

Leaky testing and clearance protocol?

Ignore the positive spin of the headline of that article. Look instead at the details. Fourteen passengers tested positive on arrival in Tianjin. They were workers. The news story emphasised that the Ministry of Health (MOH) said twelve had previously recovered from Covid-19 and were “no longer infectious”. The story then ignores the other two passengers — the silence seems to indicate that they might well be infectious. How they got clearance to join the flight is unreported.

Even those twelve whom MOH said were no longer infectious were deemed so from criteria that didn’t appear to include testing. As reported by Channel NewsAsia:

According to a time-based discharge criteria adopted by MOH, COVID-19 patients in Singapore who are assessed to be clinically well by day 21 of the illness can be discharged. The new criteria was announced by Health Minister Gan Kim Yong on May 28.

Previously, patients needed to test negative twice consecutively, 24 hours apart, in order to be discharged.

COVID-19 patients who are discharged under the new criteria will have to remain at home or at dormitories for another seven days before they can return to work after day 28 of their illness, Mr Gan had said.

Since this commentary isn’t about the Tianjin workers, we won’t go further into this incident. However, this example goes to show that Singapore’s testing and clearing matrix may be leaky.

But demanding it be leakproof may be unrealistic. Our understanding of Covid-19 is imperfect, especially as humankind has only known about it for eight months. The science is constantly evolving and ultimately we have to accept that for all the best efforts in the world, we can never be 100% sure we have eliminated it. Thus, we have to live with the chance of re-appearance in previously cleared populations.


Even though tens of thousands of dorm residents have recovered from the SARS-Cov-2 virus, the infection rate has not been anywhere near the level needed to provide herd immunity.

More worryingly, recent news reports of re-infection among people who have recovered from an earlier bout raises questions about how lasting or effective natural immunity is. In the last week alone, four cases of re-infection have been documented: in Hong Kong, Netherlands, Belgium and Nevada. See this article about the Hong Kong case, this article and this article about the Nevada case, and this article about the two European cases.

As the reports detail, the genomes of the viruses were sequenced in both the first and second infections of the Hong Kong and Nevada cases (the linked articles aren’t clear about the European cases). Scientists confirmed that the new positive tests from these two patients were not continuation of the first round of infections but new infections from different genetic strains of the virus.

Hammering down

Taken together, this possibility of re-infection and the possible fallibility of our testing and clearance protocol suggest that resurgence of clusters in dorms will not be an exception but the norm. This should be no surprise. Among our general public and in all countries around the world, clusters continue to sprout anew.

The difference is that with social distancing among our general population, and living in smaller households, the speed of transmission is lower and we need only to isolate a handful of close contacts for each case found.

With foreign workers in dorms still living 10 to 20 per room, often designed with poor ventilation, the speed of transmission will be high. By the time we discover one case, it may already have spread to many others. This means we have to isolate many more close contacts for each case found, with the result that several worksites will have to shut down with no notice, inflicting consequentially large costs to our economy.

We are using a Thor-sized hammer to deal with the proverbial fly.

Density alleviation must be top priority

Once we recognise that new clusters will inevitably appear, we need to ask ourselves how we can minimise disruption when they do appear. Re-quarantining thousands of workers is not an optimal solution. It is also a post-facto response.

TWC2 highlighted the risks from high-density accommodation very early in the pandemic. It continues to be a critical vulnerability. We would argue that there is a direct relationship between housing density (and poor ventilation) and the transmission rate of Covid-19. Reducing dorm density to shrink the numbers of close contacts is a better measure than having to slap broad quarantines. Density reduction is both preventive and mitigative.

It is always useful to bear in mind that not all foreign workers live in dorms. There are hundreds of thousands of them who live in apartments like the rest of us, and their infection rate is no worse than the low rate seen in amongst the general public. This only goes to show the difference density makes.

If we want to avoid the huge costs associated with the bluntness of our quarantine strategy, urgent action must be taken to reduce density in the dorms. Our earlier calls to use carparks, exhibition halls, sports halls, airport terminals and similar spaces to rehouse workers temporarily remain relevant today.

Workers’ accommodation should be in much smaller “households” – we suggest no more than four persons to a room – with something like 8 – 10 square metres of floor space per person. See our article Better Dormitories, Part 1 (16 May 2020).


Taking urgent steps to re-house workers into lower-density accommodation, reducing transmission of the virus, will enable us to be more liberal about letting them leave the dorms. Note again that migrant workers who do not live in dorms have the same freedoms to go out and move about as citizens and other residents; no one worries that they pose any greater risk than other members of the community. When we successfully lower the transmission rate of dorm-residents by thinning out their density, we will likewise be less concerned about them going out.

We may be stating this as a secondary benefit, but it should be a major driver of what needs to be done. Our present policy confining workers to dorms for months on end is a major human rights violation and brings shame to Singapore. It reflects the way we see migrant workers as merely objects to be used or locked away accordingly to our needs, with no regard for their humanity and mental health. It stains us as an uncivilised and heartless society.

For so many reasons, density reduction should be at the forefront of our efforts, pursued with war-like urgency. Throwing down blanket quarantines is too costly and too inhumane to be sustainable.