Pasta, it will go like this.
Sometime in Week 1, a child will test positive.
That will generate, say, 60 initial close contacts. They will be tested. Out of the group, 5 will have been asymptomatic, so if the tests were accurate (which they won't be), there should be 5 more posities. say there is 1. That generates another 20 close contacts.
Only the positive cases (2) go home. The next day goes OK. the day after, a sibling of someone in the first year group tests postitive, as does someone who catches the same bus. Now the school is processing 150 tests a day, but of course all of those students are still in school, so by the end of the week there have been a further 4 cases, so the testing number goes up to 400.
Over the weekend, family members of 4 more cases become positive (pcr tests0 so their children are tested. they too are positive, which adds another hundred or so to the original tally of tests. But of course, everyone is still in school except those 'proper' positives, so with the inaccurate tests there are still asymptomatic positives circulating...
And so on. Yes, eventually, everyone will have had Covid, a several will have long Covid, but the testing will drop down a bit....maybe by May?