Ah yes, my husband is a full-time cleaner in a large secondary school. He arrives at lunchtime (pupils are present) and works until 9pm. He starts with the toilets, and what he tells me is dreadful. The pupils make an unspeakable mess, with urine, faeces and other things. Toilet paper soaked in urine then flung up to the ceiling to stick there. (Why?)
He scours himself in the shower when he gets home, and changes all his clothes, which I'm more than happy to wash on a very hot wash cycle, including his cleaner's uniform.
He can't understand why the Headmaster doesn't address this filthiness in the toilets and punish the offenders. He didn't even have a toilet at school in Africa, just a hole in the ground!
If a pandemic broke out, I should imagine schools would be a hotbed of infection.