Eight more Covid-19 cases have been linked to the Tan Tock Seng Hospital (TTSH) cluster, including five patients from Ward 9D, where the first case in the cluster was picked up.

All eight had initially tested negative for the virus, and were picked up in subsequent rounds of testing, the Ministry of Health (MOH) said yesterday.

The remaining two cases in the community announced yesterday are linked to the Immigration and Checkpoints Authority (ICA) officer cluster.

In total, 35 cases are now linked to the TTSH cluster, while 11 are linked to the ICA cluster.

There has also been a spike in Covid-19 cases in the community, with the number of new cases increasing to 60 cases in the past week from 10 in the week before.

The number of unlinked cases in the community has also risen to 10 cases in the past week from four cases in the week before.

The five TTSH patients are all Singaporeans, aged between 53 and 94. They were transferred to the National Centre for Infectious Diseases for isolation last Wednesday.

One of them is an 82-year-old woman who had been hospitalised from April 21. She tested negative for Covid-19 last Wednesday and Saturday.

On Sunday, she was tested again even though she was asymptomatic, and her test result came back positive, MOH said. Her serology test result is negative.

Another patient is a 94-year-old woman who had been hospitalised from April 9. She tested negative for Covid-19 last Wednesday.

On Sunday, she developed a cough and then tested positive for the virus. Her serology test result is negative.

A 70-year-old man, who had been hospitalised from April 21, tested negative last Friday.

On Sunday, he was tested again even though he was asymptomatic, and his test result came back positive for Covid-19, MOH said. His serology test result is negative.

A 53-year-old woman, who had been hospitalised from last Monday, tested negative last Wednesday and Friday.

She developed a cough last Saturday, and was swabbed the next day. Her test result came back positive for Covid-19. Later on the same day, she developed a fever and runny nose, MOH said. Her serology test result is negative.

The fifth TTSH patient is a 79-year-old man who had been hospitalised from April 22. He tested negative for Covid-19 last Wednesday.

On Sunday, he was tested again even though he was asymptomatic, and his result came back positive for Covid-19 the next day, said MOH. His serology test result is negative.

The three TTSH staff who tested positive include a nurse in the TTSH emergency department.

One of the staff is a 22-year-old Malaysian national employed by UEMS Solutions who works as a porter at TTSH.

She was tested for Covid-19 last Wednesday and her result was negative. She developed a sore throat the next day but did not seek medical treatment, and subsequently had a fever and body aches last Saturday, said MOH.

On Sunday, she sought treatment at the TTSH emergency department and her test result came back positive for Covid-19. Her serology test result is negative.

Another case is a 25-year-old Singaporean nurse at the TTSH emergency department. She tested negative for Covid-19 on April 30.

She developed a fever and sore throat on Sunday, and sought treatment at the TTSH emergency department, said MOH. Her test result came back positive for Covid-19 on the same day. Her serology test result is pending.

The third TTSH employee is a 26-year-old Vietnamese nurse in Ward 9D. She was tested for Covid-19 last Wednesday and her result was negative. She was placed under quarantine last Thursday and taken to a dedicated facility the next day.

On Sunday, she was tested again for Covid-19 even though she was asymptomatic, and this time her test came back positive.

"Her serology test result was negative for the N antigen, which suggests the presence of early infection," said MOH.

She received her first dose of Covid-19 vaccine on Jan 18, and the second dose on Feb 8.

The remaining two community cases are close contacts of the 38-year-old ICA officer who had been placed on quarantine last Tuesday. One is a 37-year-old homemaker married to a family member of the ICA officer. The other is her three-year-old son.

They initially tested negative for Covid-19 last Wednesday.

Last Saturday, they were tested again even though they were asymptomatic and their test results came back positive for the infection the next day.

Her serology test result is negative and her son's result is pending, said MOH.

There were also seven imported cases who had been placed on stay-home notice on arrival here.

This takes Singapore's total number of cases to 61,235.