SINGAPORE - All the close contacts of a coronavirus-positive nurse at Raffles Hospital have tested negative so far.

They were swabbed following the positive test of the 29-year-old woman, who was one of 17 unlinked Covid-19 patients reported in the community on Sunday (May 16).

"We continue to ask the staff to closely monitor their health, and are in frequent contact daily with this group of staff to ensure they are safe, well and supported during this period," the Raffles Medical Group said in response to queries from The Straits Times on Monday.

"We are also concurrently working with the Ministry of Health (MOH) to assess the patients for potential risk mitigation."

The nurse has been discharged from the National Centre for Infectious Diseases (NCID) after being assessed as likely to be a "chronic shedder".

She will now be on hospitalisation leave at home for seven days, said a Raffles Medical Group spokesman. The private healthcare provider owns Raffles Hospital.

The nurse was well, and "we are in frequent contact to ensure (she) is supported in this period", said the spokesman.

Raffles Medical Group added that the hospital had been deep cleaned and disinfected, and operations had resumed.

"Before this positive test result, all our staff started surveillance testing for Covid-19, and this will continue for the next few weeks... to mitigate the risk of infection," said the spokesman.

She added that all the hospital's staff wear personal protective equipment according to prevailing MOH requirements and continue to abide by strict social distancing rules and split-team arrangements.

The hospital has also designated areas for the isolation for staff and patients in the event of a positive test result.

"We maintain strict isolation policies... We then work closely with MOH and NCID to determine if this positive result is a false positive, chronic shredder or new infection," said Raffles Medical Group.

The nurse arrived from the Philippines on April 1 and was under a stay-home notice order at a dedicated facility until April 14. Her swab test done on April 14 came back negative for Covid-19.

She is asymptomatic, and the infection was detected when she was tested last Friday as part of the rostered routine testing (RRT) of healthcare workers.

Her test result came back positive the next day. She had received her first dose of the vaccine on May 8.

In response to queries on how the nurse caught the virus, Raffles Medical Group said it was still working with MOH on investigations into the case.

"Our priority is first and foremost to ensure that all our patients and staff are well, and to actively mitigate any risk of Covid-19 through existing infection control protocols and RRT."