Three key questions were addressed at the multi-ministry task force's press conference yesterday following the rise in community cases and emergence of two clusters involving Tan Tock Seng Hospital (TTSH) and an immigration officer at Changi Airport's Terminal 1.

Q: Is there a link between the Immigration and Checkpoints Authority (ICA) officer's wife and the cluster at the hospital?

A: Ministry of Health (MOH) director of medical services Kenneth Mak said that so far, there has been no "obvious link" between the ICA officer's wife, who is Case 62583 and a nurse at TTSH, and the current cluster at the hospital.

"In terms of where she's gone, where she works, it doesn't appear as if it overlaps with the movement of patients or the other staff that we have now detected as part of this cluster in TTSH," said Associate Professor Mak.

However, he added that epidemiological investigations and contact tracing are still going on, and that "on an abundance of caution", the ward where the nurse had been is now locked down.

All staff and patients in that ward are also being tested, and studies are being carried out on those who test positive.

Q: Where did the TTSH cluster originate, and how did the first person get infected?

A: Prof Mak said that as epidemiological investigations are ongoing, it is not yet known for sure who the first case in the TTSH cluster actually was, and where that person might have become infected.

However, he added that the first infected person who presented herself was a nurse who reported her mild respiratory symptoms immediately after developing them, as a result of the protocols in place at the hospital.

As a result, the authorities could detect the infection and start doing contact tracing and testing.

"But she may not be the original patient that was infected, nor the cause for other patients and staff to be infected as well. So we keep open the possibility that the infection may have been introduced into the hospital by someone else," said Prof Mak.

Q: Why was a patient with symptoms moved from one ward to another at TTSH?

A: Case 62561, a 57-year-old patient at TTSH, was initially in Ward 7D and then transferred to Ward 9D.

On April 18, he went to TTSH's emergency department with a persistent fever and he developed a runny nose and cough.

He tested negative for Covid-19 and was subsequently put in Ward 7D. On April 20, he was transferred to Ward 9D.

The task force was asked why he was moved even after he displayed symptoms.

Prof Mak explained that the man had initially been placed in Ward 7D for observation. However, when a bed became available in the definitive care ward, 9D, he was transferred there.

Prof Mak added that on "an abundance of caution", all staff and patients in Ward 7D are being tested for the virus, and so far none has turned up positive.

"So we continue to be vigilant and we continue to watch to see whether or not there will be more cases that come up through our testing exercise," he said.