The number of under-fives in hospital due to influenza in England has jumped 70 per cent in just seven days – with 7.3 admissions per 100,000 in the most recent week.The number of under-fives in hospital due to influenza in England has jumped 70 per cent in just seven days – with 7.3 admissions per 100,000 in the most recent week.Read MoreHealth News | Mail Online