The children's flu vaccine helps protect against flu. It's offered to children aged 2 to 3 years, school-aged children (Reception to Year 11) and children with certain long-term health conditions. Why children are offered the flu vaccine Flu can be very unpleasant for children and can sometimes cause serious problems, such as pneumonia. Each winter in the UK, thousands of children who do not have a health condition need hospital care because of flu. Children can catch and spread flu easily. Vaccinating them also helps protect others who are at higher risk of getting seriously ill from flu, such as babies, anyone who's pregnant and older people.