SINGAPORE - There were 11 Covid-19 cases reported on Thursday (Feb 18) - all imported and placed on stay-home notice upon arrival here and tested.

Ten were asymptomatic when tested, while a 31-year-old woman who had arrived from Italy on a student's pass experienced the onset of symptoms on Feb 9.

Besides the student's pass holder, the 10 others comprised a Singaporean, a permanent resident, one work pass holder and seven work permit holders, the Health Ministry noted on Thursday.

The Singaporean, a 63-year-old woman, returned from Britain; the permanent resident arrived from Bangladesh and the work pass holder from the United Arab Emirates.

The seven work permit holders came from India, Indonesia and the Philippines.

There were three new cases in the community in the past week, down from seven two weeks ago.

The number of unlinked cases in the community in a week fell from six to one over the same period.

Thursday's new cases brought Singapore's total to 59,832.

With three more cases discharged on Thursday, 59,664 patients have fully recovered, while 20 remain in hospital, including one in intensive care and 104 in community facilities.

The sole new coronavirus case announced on Wednesday was a work permit holder who arrived from Indonesia.

The foreign domestic worker had been placed on stay-home notice on arrival in Singapore and was tested while serving the notice.

Her serology test came back positive on Monday, which indicates a likely past infection.

However, she had not taken a serology test when she arrived in Singapore on Feb 2.

The Health Ministry said it was unable to definitively conclude she was no longer infectious when she arrived.

"As a precautionary measure, we will take all the necessary public health actions," it said.

The ministry added on Wednesday that one of the active clusters last month has now been closed. Seven people had fallen ill in the police K-9 unit cluster, which developed after a para-veterinarian contracted Covid-19.

As the cluster has not had new cases linked to it for 28 days, or two incubation periods, it is now closed.

The MOH added that since Feb 5, newly arrived work permit and S Pass holders in the construction, marine and process sectors, and foreign domestic workers and confinement nannies who have recent travel history to higher-risk countries or regions have been progressively required to undergo mandatory on-arrival polymerase chain reaction and serology tests.

"These have enabled us to quickly identify persons who have recovered from an old Covid-19 infection, and are no longer infective to others by the time they arrived in Singapore, and to exclude them from our daily case count," it said.

Globally, the virus outbreak, which began in December 2019, has infected more than 109 million people. More than 2.4 million people have died.