Does evidence that teenagers do pass on the virus and haven't been adhering to SD enough.
And of course these pupils have now been back at school with ....other pupils ....and staff.
Time will tell if:
Government 'safety measures' for schools are enough
Pupils and staff are immune within a school 
'All schools reopening in September' is really, some schools, sometimes, for some pupils...so not really open at all.
Hope employers are going to be supportive of their staff requiring time at home when school is closed, when pupils need collecting throughout the day, when there aren't enough teachers and when testing needs to happen.