I hate the way that 'underlying halth issues' seems to be a re-assurance - an indication that everyone can go 'oh, that's ok then' (in the reporting - I'm not saying that's what MNers do).
It isn't OK. It means that thousands of parents of disabled or vulnerable children, who have happily recovered from a range of childhood illnesses such as colds, flu, cp etc, are terrified that this illness may take thier child.
And from schools I have contact with in London, I think it's being under-reported. I mean, more children have died.