Three students, a pre-schooler and a housekeeper at Sengkang General Hospital are among 18 new cases in the community announced on Tuesday (May 25).
The affected schools are Westwood Secondary School, Kranji Secondary School, Rulang Primary School and My First Skool at Block 211 Jurong East Street 21, said the Ministry of Health (MOH).
The 15-year-old student from Westwood Secondary School is one of six unlinked cases.
He was last in school on May 18.
The student developed a fever and runny nose last Saturday and was tested for Covid-19 on Monday after seeking treatment at a polyclinic.
The other children are linked to previous cases.
The 13-year-old student from Kranji Secondary School and the seven-year-old pupil from Rulang Primary School are linked to the Jem and Westgate cluster, which has grown to 53 cases.
The 13-year-old was last in school on May 17 and the seven-year-old was last in school on May 14. Both developed symptoms on Sunday.
The pre-schooler is a family member of two previous cases and was placed on quarantine on May 21.
The six-year-old boy is asymptomatic and was detected when he was tested for Covid-19 during quarantine.
The 27-year-old Sengkang General Hospital housekeeper developed a fever on Sunday and was tested when he sought medical treatment at a polyclinic on Monday.
Also infected is a 29-year-old who works at the Tiger Sugar bubble tea shop in the Holland Piazza shopping mall. He is among the six patients whose infections are currently unlinked.
A delivery rider for Domino's Pizza in Tanjong Katong, a kitchen staff from the McDonald's outlet at Pasir Ris Elias Community Club and a kitchen staff from the McDonald's outlet in Bedok Reservoir were added to the cluster linked to McDonald's delivery riders. The cluster now has 13 cases linked to it.
There were also three new clusters announced by the Ministry of Health.
Of the three, one of them is linked to the Harvest @ Woodlands dormitory after three cases were reported in the dormitory on Tuesday.
The 30 new cases take Singapore's total to 61,890.
Separately, the ministry also said 116 residents and visitors to Block 559 Pasir Ris Street 51 have tested negative for Covid-19.
They were swabbed after four cases were detected in two different households there.
In total, 304 people were found negative as at Tuesday.