How many more tests for Foreign Workers? An attempt to break down the information with facts.

Another day, another 500 Covid19 cases from the Dorms

You are probably wondering, after 2 months of testing, when would this end?

The reality is this. Given the extensive spread of the virus throughout Foreign Workers Dorms in Singapore, the only time that the numbers will come down would be when the testing stops. In a recent newspaper report, it was stated that proactive screening of migrant workers may take up to August or September. 

How many Unique Test Done?

We first take a look at the number of swabs test done between 18 May and June 1.

Source: MOH

May 18 

Swabs Test Unique Persons: 191 260

Source: MOH

June 1 

Swabs Test Unique Persons: 264 393

Total Swabs Test Unique Persons: 73 133

Number of days from May 18 to June 1: 15 days (inclusive of May 18 and June 1)

Average Tests per day: 4875

Note that this number includes Pre School Staff being tested From May 16 to 26. There are a total of 33,000 preschool staff tested. As a rough average, there are 3000 staff-tested daily. Thus, the total number of tests from May 16 to May 26 is estimated to be 27,000.

If this is deducted from the Total Unique person tested, the final number tested would be about 46133 during the period. This would include test for the community. If we assume 100 tests per day for the community, over 15 days, there would be about 1500 tested. The numbers tested for dorms will thus be around 44600. This is just an estimation and may not reflect the actual number.

% of Infection.

To have a sense of the infection rates in dorms, we use the total number of cases in dorms to deduce the rate.

May 18:303

May 19: 450

May 20: 562

May 21: 434

May 22: 610

May 23: 631

May 24: 544

May 25: 338

May 26: 381

May 27: 529

May 28: 372

May 29: 602

May 30: 501

May 31: 516

June 1: 408

Total: 7900

% Infection (assuming 44600 Tested) 17.7%

How many are tested to date?

There is no indication of how many Foreign Workers were tested. As mentioned earlier, Mr Gan did indicate that proactive testing might last till August or September. If we were to test an average of 3000 cases per day for 90 days ( from now to Sept), we might be looking at another 270,000 tests.

Additionally, 40,000 Migrant Workers were cleared from infections on June 1. This includes those who were positive but fully recovered and discharge. As of 3 June 2020, There are 12799 active cases with the majority being Foreign Workers. Thus it can be estimated that about 50,000 workers are tested to date. 

This is about right as our previous article 'Dark Days Ahead for Singapore', it was estimated that 323,000 FW are currently living in dorms. To add on, there is another estimated 410,000 Work Permit Holders living outside dorms. 

Source: MOM

Base on the figures, we would have tested about 15% of the FW in dorms. 

There is another report that stated that more than 202,000 tests were done on community population which includes Singaporeans, permanent residents and all long term pass holders. There are a total of 408,000 swabs test done to date, with 264,393 unique cases. If that is the case, we can assume that at least half of the unique cases are Foreign Workers ( estimated 132K cases) This may include FW living outside of dorms. If not the numbers tested in dorms could eventually be about 50K-132K. 

Base on the figures, a safer estimation would that 15-40% of the FW in the dorms tested.  

To put things in perspective, out of the 737K Work Permit Holders (excluding FDW), we have a staggering 605K more test to go.

Analysis

As seen from above we would have another 60-85% more to test in the dorms. That translates to 190K to 275K FW.

If the rate of infection in dorms stands at 17% (base on tests from May 18 to 1June), we have potentially another 32K to 46k of possible infection. If that is the case, it will double the tally as of today and we might even overtake China as a result. Our earlier analysis has an estimation of 120K cases from dorms itself base on the extrapolation of the cases found.

Nonetheless, this figure is base on a crude estimation. Thus the final tally might be lesser than this for a few reasons

• It is highlighted that there are many asymptomatic cases that would not be infections after 2 weeks. 
• By the time the tests concluded, the majority of those tested positive might fall into this category.
• Not all FW might be tested

Suggestions to improve transparency

To avoid any doubts, it would be best that the following information are made known to the general public.

1) Number of Tests concluded for FW in Dorms

2) % of Infections

3) Number of Tests to be done for FW in Dorms

Given that there are still community cases for FW outside dorms, we proposed the following as well. In order to effectively control spread and reduce the reservoir of undetected cases, FW living outside of dorms are to be tested as well. 

Thus the following information would be useful too.

1) Number of Tests concluded for FW outside Dorms

2) % of Infections

3) Number of Tests to be done for FW outside Dorms

We do hope that this storm will pass quickly over us. However, given the presented scenario, the conclusion is still months away. It will be a bumpy ride ahead especially when we are debating if we should shift to Phase 2 or even 3 in opening up the economy.

Disclaimer

The numbers are an estimation. As we do not have the full information from MOH, we can only deduce. The analysis is base on assumptions and may not fully reflect the fact.