No additional Covid-19 cases from Ang Mo Kio-Thye Hua Kwan Hospital have been detected so far after a 17-year-old nursing student from the community hospital tested positive for the virus on Monday.

The ward she worked in has been locked down, with non-essential services there suspended, the hospital's chief executive, Mr Ardi S. Hardjoe, said yesterday.

The affected ward is also not accepting visitors and will not be admitting or discharging patients.

"Visitors who were affected were informed via SMS and direct calls to inform them of the new measures, and to assure them that the safety and care of the patients will not be compromised," said Mr Ardi.

"We have not had any increase in the number of queries from concerned family members. They have been quite understanding of the situation and only asked when they could visit their loved ones when safe."

Meanwhile, the hospital has disinfected and deep-cleaned areas the student nurse spent time in.

Patients and staff who could have been in contact with her have also been tested, said Mr Ardi, who added that the hospital has not detected any other case. Repeated swab tests, however, will be arranged for patients and staff.

He said 86 per cent of the staff have been vaccinated.

The student, who started her internship at the hospital on May 17, had adhered to all safety protocols and personal protection guidelines while attending to patients in her assigned ward, said Mr Ardi.

She was last at work last Friday, and her swab test from rostered routine testing on May 25 came back negative.

But she developed a fever and sore throat on Sunday, and went to a general practitioner clinic the next day. She tested positive that same day.

The student is linked to the Hong Ye Group cleaners cluster, which had 25 cases as at Tuesday.

She is a close contact of another infected case - an 18-year-old full-time national serviceman at the Civil Defence Academy. He is a family member and household contact of three cases linked to the cluster.