It's absolutely no fun for five year olds to avoid eachother and be sat at a desk all day with no carpet time and minimal outdoor time
Maybe have some faith in the teaching staff that they have got this and will do everything they can to make it fun? It's different, yes, but it doesn't have to be some gut-wrenching, hand-wringing agony, does it? Your child will take cues from you: approach it with a light heart and some positivity and see how that works for your child?
I think the mental health affect on children is going to be huge
Article on the BBC website today begs to differ. Again, your child will take her cues from you. Be positive.
Long term though what does that mean for them. Phobias of germs, people, places. Anxiety
Or maybe they will learn about community, about what it means to have empathy and support people around them who may be more vulnerable and stop them getting sick? Does it have to be a negative experience? Do they need to come away from this with anxiety or phobias of germs? What cues will your child be taking from you on this issue? What is wrong with regular hand washing? Not wiping snot all over your friend? Having a bigger space to work in? Learning to work independently?
As a teacher, I can tell you OP I am sick to death of reading this bullshit. Teachers are going to get sick and some are going to die. Russian Roulette we'll be playing come September 1st. Put it into perspective, eh? Your child's teacher's will approach this with a smile on their face and total professionalism so support that rather than making problems where there aren't any. Plenty of schools are putting in place half-arsed plans which will result in closure quickly. At least your children's school is trying and with a bit of luck, will be open for the duration with few or no interruptions. Try glass half full, perhaps?