Parents are warned that the flu season is under way, after the number of children aged five to 14 falling ill doubles.
Doctors have advised that it is not too late to have a vaccination, and that anti-viral drugs should be administered for people at risk of developing complications from flu.
Flu symptoms include sudden onset of fever, cough as well as sore throat and aching muscles and joints.
The flu season was declared by the Health Protection Agency (HPA) after an increase in reported cases among children aged five to 14, both from GP consultations and respiratory outbreaks in schools, as well as from calls to NHS Direct.
There was a 50 per cent rise in GP consultations for flu among children aged 5 to 14 last week, reaching nearly 50 per 100,000. Among the general population, flu consultations rose by 64 per cent, to 23.4 cases per 100,000.
The increase in cases follows an outbreak of the norovirus winter vomiting bug this season, raising concerns of a Christmas ridden by illness.
The Department of Health has approved the use of antiviral drugs and issued guidance on their use, for those who are at higher risk of developing complications from flu.
Reports of flu are highest in north east England, according to a London School of Hygiene and Tropical Medicine survey.
“Flu vaccination is still the most effective way of preventing flu and it is not too late to get it so we would encourage all those who are in ‘at risk’ groups to get vaccinated as they are more vulnerable to developing complications from flu,” said Dr Richard Pebody, head of seasonal flu surveillance at the HPA.
“These include people with underlying conditions such as heart problems, diabetes, lung, liver or renal diseases and those with weakened immune systems, as well as older people and pregnant women.”
The best advice for treating flu in healthy people is to stay at home, rest, drink plenty of fluids and take pain relievers such as paracetamol. Children under 16 should not take any medicines containing aspirin.