Officially, it is still 17 percent, going by international standards of case counting (i.e. PCR-positive). But if we add in the workers who have been found to be serologically-positive, then it gets to 47 percent.

The new figure is from a relatively long press release by the Ministry of Manpower (MOM), 14 December 2020. The press release can be found here:

The bottom line is that 47 percent of migrant workers staying in dormitories have previously been infected with or exposed to Covid-19.

According to the statement, 54,505 migrant workers living in dormitories have so far tested positive via the polymerase chain reaction test (PCR). Since this test detects fragments of the virus, it means that at the time of the positive test result, they had the virus in them.

These 54,505 make up 93.5% of the 58,320 PCR-positive cases found so far in Singapore, and about 17.0% of the roughly 320,000 dormitory residents here. Virtually all, if not all, have since recovered, minus the two migrant worker fatalities that Singapore has seen.

A few months into the epidemic, serology tests began. This procedure detects antibodies and a positive result would indicate a past exposure to or infection with Covid-19. MOM’s statement says that so far 98,289 workers have tested positive in serology only.

Adding the two numbers together, there were 152,794 workers who tested PCR-positive, serology-positive or both. These were 47% of the 320,000 foreign workers living in dormitories.

We use the term “prevalence rate” in the above table because MOM used that term in its statement. It is somewhat misleading as the term is usually used to mean the proportion with an ongoing condition. In this case the numbers actually refer to workers who had (past tense) the condition. So while the figure of 47% looks high, it does not mean that they are infectious. More likely, it means these guys have recovered and now have immunity!

Previous data about Covid-19 infections referred to positive PCR cases and as far as we know, this is the first time we’ve seen data about serologically-positive cases as well.

That said, there are another 65,000 workers who have not yet undergone a serology test. So, the number of serology-positives is likely to increase over the next few weeks and the 47% figure may go up as a result.

The MOM statement further explained:

Among the migrant workers who tested PCR-positive or serology-positive, the vast majority were asymptomatic or had very mild symptoms. Only about 1 in 5 of migrant workers living in [purpose-built dormitories] presented with symptoms, with the remaining 4 in 5 displaying very mild or no symptoms.

Note: Of 320,000 workers in dormitories, about 200,000 were in purpose-built dormitories. The rest were in either factory-converted dormitories or temporary construction quarters. Consequently, the above ratios from MOM do not map over the statement’s other numbers.

Not all cases were isolated

During the worst of the pandemic, TWC2 had heard from many workers, following test results showing them to be positive, that although they were expecting to be moved out to isolation, they were in fact told to continue staying in their quarters. They remained in proximity to other roommates.

This “remain-in-place” instruction didn’t make sense at the time, though even then, we noticed that such reports were coming from workers with no symptoms or just the mildest of symptoms. Until now we have no clarity why those workers were not moved out, but the consequences are now evident — a very high prevalence rate six months after the peak of the dorm crisis.

TWC2’s observation is corroborated by this paragraph in MOM’s statement (or at least the silence contained within):

At the same time, any worker who reported sick or showed symptoms of acute respiratory infection during this period was isolated, and given medical care regardless of whether he had received a PCR test.

It speaks of isolation for those who were clearly sick or had respiratory distress. The statement does not mention isolation for less serious cases.

The statement reiterated the generally good outcomes for migrant workers who tested PCR-positive:

Despite the scale of the outbreak in the dormitories, the morbidity and mortality rate among our migrant workers has been very low. There were 25 COVID-19-related ICU admissions amongst migrant workers living in dormitories and only two deaths due to COVID-19, including one of those who had been admitted to the ICU.

However, more recent indications are that even those who were asymptomatic may experience long-term effects of Covid-19. TWC2 has a story about two men felled by heart attack and stroke — and we know of two more with similarly severe thrombotic events — months after asymptomatic Covid-19. See: Two men seriously ill with long-term Covid-19.

How many more are going to be likewise impacted? The 47% prevalence rate should be read with some concern.

Still imprisoned

MOM said in its statement:

Since October, no new cases were detected in the dormitories on many days.

And yet, migrant workers are still locked up in their dorms and only allowed:

  • to be taken out for work by their employers, who should return them to the dorms after the shift;
  • a three-hour break once a week during which they are only to visit designated shops nearby.

Workers are still interned and treated like prisoners, used for their labour with no freedom of movement.

MOM speaks of a “pilot scheme” in the first quarter of 2021 as part of the Phase 3 re-opening of Singapore to allow migrant workers in some dormitories to “access the community” once a month. That probably means they may get one day (full day? a few hours?) when they can go out as they please.

This is still shockingly restrictive. Since the active infection rate is virtually zero and they are now tested regularly every two weeks, there is no reason to keep them locked up.

Singaporeans enjoyed a loosening of the lockdown when we were still finding a number of positive cases in the community. In the left-side table below, we tabulate  the daily number of infections in the community in the ten days prior to the Phase 2 re-opening on 19 June 2020. Since then, restaurants and cinemas have opened, public transport have returned to regular services, and even “cruises to nowhere” have resumed. But just prior to that 19 June re-opening, we were not at zero cases in the community. We were experiencing a daily average of 6.4 new cases of Covid-19 in the community and yet we felt safe enough.

The table on the right shows the number of new cases in the previous ten days. There were an average of 0.1 cases in the community and this is such good news that the Prime Minister himself went on television to announce a Phase 3 re-opening on 28 December 2020 — for the non-dormitory community only.

MOM’s announcement of the same date speaks of one day out each month for dorm residents. But as the table shows, the infection rate among dorm residents in the last ten days is also 0.1 on average.

Does this not speak of egregious discrimination?

It may be argued that because these foreign workers are housed like battery chickens in coops  — and whose fault is it for this situation? — should even one infection take hold among them, it can spread like wildfire. Thus, going by this logic, even 0.1 infection per day represents a serious risk.

But consider the other statistic: the prevalence and thus immunity rate is 47%. That’s nearly herd immunity. What is there to fear?

Open the dorms!