SINGAPORE - The number of Covid-19 cases linked to the Tan Tock Seng Hospital (TTSH) cluster has grown to 13 as of Friday (April 30).

The cluster emerged following the diagnosis on April 27 of a nurse who works in a general ward. 

Here's what we know so far about Singapore's first Covid-19 hospital cluster.

1. When were the cases detected?

A fully vaccinated nurse from TTSH tested positive for Covid-19 on April 27. The 46-year-old Filipino woman developed a cough, sore throat and body aches, and sought medical treatment at TTSH. 

She was deployed at Ward 9D, a general ward.

2. Who are among those affected?

As of April 30, 13 TTSH patients and staff have tested positive for Covid-19. They include six patients, a doctor and a healthcare assistant trainee.

One of the patients is a 72-year-old woman who developed symptoms associated with Covid-19 while staying in a general ward at TTSH. Madam Ong Kim Choo's infection was detected on April 28. She was admitted to a C class ward on April 20 for rheumatoid arthritis.

Madam Ong, who has not been vaccinated, told The Straits Times that she is highly concerned about her family. She said: "I am worried about my grandson. I told them not to visit me. Now, their family life has been affected." 

3. What is the likelihood of more cases emerging?

Singapore expects to detect more Covid-19 cases linked to this cluster in the coming days, said Health Minister Gan Kim Yong on April 30. The authorities may take more stringent measures should widespread transmission be found, he added.

"These recent cases are another reminder that the virus is alive and circulating," Mr Gan said, urging Singaporeans to continue to be socially responsible and stick to the safe management measures, even if they have been vaccinated.

4. What are the measures taken so far?

All 1,100 inpatients and 4,500 staff working in the TTSH wards will be swabbed as part of a mass screening exercise. 

The hospital has also locked down four affected wards to stem the spread of the virus. Staff and patient movement in all the main wards has been minimised to prevent cross-infection, and no visitors are allowed into the hospital except for critically ill patients. 

5. What does a lockdown of TTSH wards entail?

"When a ward is locked down, this means that there is no in-or-out movement within the ward, with restricted movement for both patients and staff, and only for essential testing, such as a test in the radiology department, for instance," said TTSH chief executive Eugene Soh.

In addition, a dedicated group of staff takes care of the ward.

6. Are there other precautionary measures taken?

All public places visited by Covid-19 cases who are part of the TTSH cluster during their infectious period will be closed for two days for cleaning.

The list of places visited by the patients during their infectious period, from April 15 to April 27, include NTUC FairPrice outlets, eateries, Orchard Road stores and mosques.

7. What are the experts saying about the cluster?

The TTSH cluster is of concern, but there is no need to be overly worried, said several experts. 

Professor Dale Fisher, a senior infectious disease consultant at the National University Hospital (NUH), said: "We know Covid is very unforgiving. Such a cluster could have occurred anywhere and we just have to make sure that if there is a case at a hospital, it will be picked up and not allowed to spread."

This article was first published in The Straits Times. Permission required for reproduction.