Grandad1943 Teachers generaly suffer a high level of communicable diseases because of the close contact they have with children. Usually when they are sneezing/coughing/running a temperature and suffering loads of other symptoms they will struggle into work because they know that if they don't extra responsibility will fall on the shoulders of their over worked colleagues. However the situation now prevents them doing this, so they are self isolating as instructed, and of course the temperature/cough may turn out not to be Covid19, but would you really want them to take a chance on that?
I wish you would realise that teachers have no more desire to skive off than any other members of the work force, and indeed most have far less because of their commitment to both. the children they teach and their colleagues.