Antigen rapid tests piloted for quicker detection of Covid-19 infection among migrant workers

Foreign workers in SCM Tuas Lodge dormitory taking antigen rapid swab tests, on Oct 25, 2020.
Foreign workers in SCM Tuas Lodge dormitory taking antigen rapid swab tests, on Oct 25, 2020.ST PHOTO: MARK CHEONG

SINGAPORE - To quickly detect and isolate asymptomatic Covid-19 cases among migrant workers, the Ministry of Manpower (MOM) and the Ministry of Health (MOH) have started piloting the use of antigen rapid tests, which can give results within half an hour.

The new tests will form part of the existing rostered routine testing (RRT) of workers staying in dormitories, which has helped pick up new infections among them.

Under the RRT, workers are already tested every 14 days using the polymerase chain reaction (PCR) test. However, it takes at least a day for the PCR results to come back.

The pilot programme comes as agencies work out ways to incorporate fast testing into Singapore's Covid-19 response, including having such rapid tests available at certain mass events in the coming months.

On Sunday (Oct 25), Dr Lam Meng Chon, medical director of the MOM’s Assurance, Care and Engagement (Ace) Group that supports migrant workers and dorm operations, said this “helps to break the chain of transmission and reduce the risk of spread within the dormitories”.

He added that by increasing the testing frequency, they would be able to pick out positive cases that might have otherwise slipped through. 

The pilot, which was started last Sunday (Oct 18), will involve some 1,000 workers staying at SCM Tuas Lodge dormitory.

The antigen rapid test will be used as an additional test on the seventh day of the 14-day RRT cycle, to complement the PCR tests on the 14th day. This means that workers will have to take a Covid-19 test every seven days during the pilot.

Results from the antigen rapid tests are out within 30 minutes. A nasal swab is used to take a sample from the lower part of the nose.

Such tests, however, are less accurate than PCR tests, which are currently used to definitively confirm coronavirus cases and remain the most accurate tests available today.

Dr Lam noted that because of the lower specificity of the antigen rapid test, a positive case is just a suspected Covid-19 case.

Those who test positive will be isolated immediately and sent for a confirmatory PCR test. 

However, fewer close contacts will need to be quarantined, minimising work disruptions for workers and employers. 

The pilot will run for a period of four weeks before its effectiveness is assessed. If it works well, it may be scaled up and expanded to cover more migrant workers.

Ms Koh Guat Siew, vice president of human resource operations at Sembcorp Marine, said the company can take action earlier if the test results are out sooner. 

She noted that workers can quickly return to work if they test negative. “We can be assured that once a worker goes back to work, the risk is minimal,” she added.

Workers said the long wait for the results from the usual PCR tests can be quite worrying.

Quality control technical engineer Sikder Masud, 34, who took the antigen rapid test last week, said: “But with the (antigen rapid test), I can get the results faster and it is less uncomfortable. I also feel safer when I go to work.” 

Last Tuesday, MOH said that pre-event testing for Covid-19 will be a requirement at certain mass events in the months ahead.

Participants will have to take an antigen rapid test and obtain a negative result before they can gain entry, under a new pilot programme meant to help Singapore resume more activities safely.

These tests can be conducted at the event venue or at an off-site testing facility.

Those who test positive must self-isolate and go for a PCR confirmatory swab. They cannot leave their place of isolation until a negative result is received.

The large-scale events where rapid testing will take place will include business-to-business events, wedding receptions, live performances and sports events.