According to this recent article
40 to 50 child related covid admission per day and 1 in 7 children who get covid go onto get long covid.
I assume these figures just relate to England not whole of UK its wrote like that as gavin is not education secretary of the devolved nations.
Child covid infections and admission expected to go up.
inews.co.uk/news/world-scientists-warn-gavin-williamson-reckless-pupils-health-covid-19-infections-1181705
I did know child admission in hospital for covid exceeded 1000 in July and were high in August and this is before schools return with zero safety mitigations!