SINGAPORE - Colleagues who were in close contact with a housekeeper at Sengkang General Hospital (SKH) are now under quarantine, after the 27-year-old man tested positive for Covid-19 on Monday.

The man had not had any contact with coronavirus patients, and had also adhered to proper precautionary measures such as wearing personal protective equipment while at work, the hospital said.

It added that contact tracing and surveillance swab tests are ongoing, and additional measures - such as intensive disinfection of the relevant areas - have been taken to mitigate the risk.

The man was last at work on Saturday and developed symptoms on Sunday night. He visited a polyclinic on Monday, when he was tested for Covid-19.

"We remain on heightened vigilance to keep our patients, their family members and our staff safe," SKH said in a Facebook post. "This includes proper wearing of face masks, proper hand hygiene and following all safe distancing measures."

It has also reinforced the importance of infection control, adhering to safety measures and exercising personal responsibility when ill.

The Malaysian housekeeper, who has not been vaccinated against Covid-19, is in an isolation ward at SKH and doing well.

His most recent swab test done as part of the hospital's proactive surveillance testing efforts, last Friday, had been negative.

He was isolated after an antigen rapid test came up positive on Monday, with a polymerase chain reaction test later confirming the result.

In a separate post, Ng Teng Fong General Hospital and Jurong Community Hospital, which share a campus in Jurong, said they would be conducting a second swab test on all staff and vendors.

This is a precautionary measure given the Health Ministry's decision to shut Jem and Westgate malls nearby for two weeks, following likely ongoing transmission among visitors to both places.

Staff who visited the malls from May 10 have been advised to closely monitor their health for two weeks and seek immediate treatment if unwell.

The hospitals had carried out a first swabbing exercise early this month, as part of surveillance testing against Covid-19.