SINGAPORE - More than 5,500 workers have been tested as part of a pre-emptive Covid-19 testing operation across various dorms and worksites from last Friday to Monday (April 23 to 26), said the Ministry of Manpower (MOM) on Wednesday.

The authorities are carrying out this precautionary measure following the cluster at Westlite Woodlands Dormitory which has seven cases so far, including five who were reinfected. In all, 26 residents at the dorm had tested positive for Covid-19, though of these cases, two subsequently tested negative while another 11 were assessed to be shedding virus fragments.

These tests are in addition to the rostered routine testing conducted on dorm residents every 14 days, and includes both workers who have recovered from previous infections and workers who have never been infected, said MOM in a statement.

Among the more than 5,500 workers tested are those who come from the worksite related to the earlier confirmed cases, as well as workers from other dorms who have come into contact with them.

Not all who were tested are recovered workers, and some of them are cases that have not been infected with Covid-19 before.

The pre-emptive operation was carried out by the MOM's Assurance, Care and Engagement Group, along with the Ministry of Health, the Building Construction Authority (BCA) and the Economic Development Board.

The precautionary testing operation comes after a group of reinfected workers were detected at Westlite Woodlands purpose-built dorm recently.

On Tuesday, the Ministry of Health (MOH) said that after a special testing operation at the dorm, 24 recovered workers were found to be positive, although two of them were subsequently determined to be negative after retesting.

Five of the 24 were determined to be likely cases of reinfection, while 11 were assessed to be shedding virus fragments. The remaining six cases are pending assessment by an expert panel.

Of this breakdown, MOM said on Wednesday that this showed that most Covid-19 positive cases among recovered workers may be assessed to be old infections.

Recovered workers

When recovered workers are tested, MOM said it expects a proportion of them to return a positive result on the polymerase chain reaction (PCR) test.

But "this does not necessarily mean that the recovered worker has been reinfected. Many recovered workers can test positive because of prolonged shedding of viral fragments from an old infection", it said.

These cases require further clinical assessment over several days to determine whether they are old or current infections, said MOM, and movement restrictions or quarantines may be imposed on a dorm if a few residents test positive.

"The precaution is necessary for the duration of this assessment and will be lifted upon the testing operations' conclusion," said MOM.

When quarantines are imposed at dorms, this does not necessarily mean that there are confirmed clusters there, the ministry added.

"Most of the time, it is because cases are being assessed to determine if they are old or current infections."

Precautionary steps

MOM said precautionary steps have been taken to protect workers who are well and to curtail the risk of transmission.

The BCA has stepped up inspections on safety measures at construction worksites as well, it added.

Dorm residents can still access in-dormitory communal facilities and recreation centres, but the usage will be regulated to reduce the inter-mixing of workers.

Movement between dormitory blocks continues to be disallowed.

"Workers have also been advised to cease social interactions with others who do not reside in the same room or floor," added MOM.

It assured affected migrant workers that access to round-the-clock medical assistance remains available, with measures also in place to look after their mental well-being, which includes counselling hotlines in their native languages.

It also said affected workers will continue to be paid their salaries for the duration of the quarantine, and their period of absence from work will be treated as paid hospitalisation leave, as part of workers' leave eligibility.

"MOM appreciates the contributions and cooperation of our migrant workers as we do our best to protect them by decisively managing potential clusters of infection from forming. Measures such as quarantine are not conducted for longer than necessitated by public health reasons," the ministry said.

The ministry urged employers and dormitory operators to remain vigilant, ensure safe management measures are followed and send workers for rostered routine testing in a timely fashion.