Education Minister Ong Ye Kung, who visited the JC, said this attendance rate was very normal, and that students were in good spirits.
But he added that he was troubled to learn that some members of the public shunned students in uniform and denied them service.
"This is not what we stand for in Singapore, and I am sure the few don't reflect the larger population," he wrote in a Facebook post.
He added that he was cheered to hear many students express their desire for school life to continue as far as possible with precautions, despite some calls for school closures.
Yesterday was the first day back at school for the JC's students since the Health Ministry said last Friday that a teacher there had been infected with the virus. All staff and students who had been in recent contact with the teacher were serving a 14-day leave of absence.
Separately, just one in 10 children attending Pat's Schoolhouse Kovan, which is linked to a new coronavirus case, turned up for school yesterday.
This was even after some students and teachers were placed on a 14-day leave of absence, and the school disinfected its premises.
On Sunday, the Health Ministry announced that a 71-year-old man, who reported onset of symptoms on Feb 1, was confirmed to have the coronavirus infection.
He had picked up his grandchild at Pat's Schoolhouse Kovan before he was admitted to hospital.
The news evidently spooked parents, with only one child seen turning up for class during the drop-off time frame from around 8am to 9am. This was even though the school was conducting classes as normal.
A couple dropped their child off at the pre-school yesterday. While they are worried, they said they believe the school will “ensure a safe and clean environment for the children”.
Mr Ronald Kwong, director of operations at Busy Bees Singapore, which runs the Pat's Schoolhouse pre-schools, said the attendance rate was about 10 per cent.
On the school's decision to place affected students and staff on a leave of absence, Dr Piotr Chlebicki, an infectious disease specialist at Mount Alvernia Hospital, said most parents need not worry.
"Unless the grandfather had gone into the classrooms and spent time playing with all the children, there is no reason to do anything."
Pat's Schoolhouse is one of the more expensive players in the industry and is popular among parents for its bilingual curriculum.
Mr Kwong said the Kovan centre - the largest of 15 - "undertook additional disinfection of the entire premises, including external areas, when we were alerted of this case".
The frequency of disinfection and sanitisation has been increased across all its centres. Health checks, including temperature-taking, are also conducted at least thrice a day for children and staff.
Aside from the pre-school, the grandfather had also visited Paya Lebar Methodist Church.
The Methodist Church of Singapore yesterday said Paya Lebar Methodist Church would be sealing its premises for a thorough sanitisation.
The kindergarten at the church will also be closed for cleaning until further notice.