Most of the 27 recovered workers in Westlite Woodlands dormitory who have tested positive for Covid-19 are unlikely to be cases of reinfections, the Ministry of Health has found.
In an update yesterday, it said that 20 positive cases from the dormitory have been assessed or preliminarily assessed to be shedding virus fragments of old infections, while two cases have been determined to be negative for Covid-19 after a retest.
However, five workers who are roommates of a vaccinated worker in the dormitory who had earlier tested positive are likely to be cases of reinfection.
Their close contacts in the dormitory and at their workplace have been quarantined.
The first of the seven cases that formed the cluster is a 35-year-old Bangladeshi construction supervisor who was confirmed to have Covid-19 on April 19, despite having received both doses of the Covid-19 vaccine.
Following that, his roommate who had also received both jabs - the first on March 13 and the second on April 3 - also tested positive for Covid-19 on April 21.
Since then, more than 5,500 workers have been tested as part of a pre-emptive Covid-19 testing operation across various dormitories and worksites from last Friday to Monday, said the Ministry of Manpower on Wednesday.
These tests are in addition to the rostered routine testing conducted on dormitory residents every 14 days, and include workers who have recovered from previous infections and those who have never been infected.
Following the emergence of this cluster, the multi-ministry task force tackling Covid-19 tightened safeguards for migrant workers to reduce the risk of reinfection among workers who have recovered from the virus.
Among other measures, newly arrived migrant workers with a positive serology result will now have to go through a rostered routine testing regime, where they will be tested every two weeks. They were previously exempt from this requirement.