The Ministry of Health contacted Kaiapoi High, which has a roll of nearly 900 pupils, yesterday afternoon.
Ministry officials requested that all "staff and students need to go into isolation effective immediately" for the next two weeks.
It is more than the mandatory isolation that all New Zealanders will be experiencing from tomorrow – with self-isolation meaning that even in the home, people need to separate themselves from those they live with as much as possible and limit contact with people other than the people they're self-isolating with.
"I know that this is not the news that you will want to hear. This affects a large group of our community," Kearney says in his email seen by the Herald.
"My heart goes out to you all at this difficult time."
He asks people to follow Ministry of Health guidelines, especially as given that staff and students will all be in self-isolation, "there is little that the school can do".
"We will keep you up to date there is any changes to the circumstances. Staff will continue to make contact as per our pandemic plan," he adds. "I am sorry to have to share this with you all."