SINGAPORE - A 41-year-old Singapore Airlines (SIA) cabin crew member who was on a turnaround flight to the United Arab Emirates is the fifth person on that aircraft to test positive for the coronavirus.

All five have also tested preliminarily positive for the more infectious B117 strain of the coronavirus, the Ministry of Health (MOH) said on Tuesday (Feb 9).

The stewardess, who is Singaporean, was among 11 coronavirus cases confirmed by the MOH on Tuesday. The new cases, all imported, take Singapore's total to 59,732.

The four others are passengers, all dependant's pass holders, and were confirmed positive for Covid-19 earlier this month. They include a three-year-old girl and a one-year-old boy.

"In view of her recent travel history, and the possibility that she might have been infected on board the flight, we have preliminarily classified this case as imported," said the MOH. Meanwhile, all the identified close contacts of the patient have been isolated and placed on quarantine, it added.

The air stewardess departed Singapore on Jan 30 on the flight to Dubai and returned on Jan 31 without disembarking from the aircraft.

She also received her first dose of the Pfizer-BioNTech vaccine on Feb 2. "As the vaccine does not contain live virus, she could not have been infected due to vaccination," said the MOH. "It is possible for one to be infected just before or just after vaccination, as it typically takes a few weeks for an individual to build up immunity after completing vaccination."

She developed anosmia - loss of the sense of smell - on Feb 4, but did not seek medical attention, said the MOH. On Sunday, she was tested for Covid-19 as part of the Civil Aviation Authority of Singapore's requirements.

Her pooled test came back positive for the virus on Monday, and she was taken to the National Centre for Infectious Diseases for an individual swab, and isolated. The later test came back positive for Covid-19 the next day.

Her previous test on Jan 22 following another turnaround flight was negative for the virus and her serology test result came back negative, indicating that this is likely a current infection.

The remaining 10 imported cases tested positive while serving stay-home notices on arrival in Singapore, said the MOH.

They came from several countries including Indonesia, India and Russia.

The MOH added that Oasis Terraces and Ci Yuan Hawker Centre in Ci Yuan Community Club were added to the list of places visited by Covid-19 patients while they were still infectious.

Singapore has had 29 deaths from Covid-19 complications, while 15 who tested positive have died of other causes.

Correction note: MOH has clarified that the Singapore Airlines stewardess returned to Singapore on Jan 31, not Feb 1 as earlier reported.