Health chiefs have warned that thousands of children in Brighton and Hove are still being left unprotected against flu this year.
Children do not even need to worry about needles, with the vaccine available as a nasal spray.
But missing out could expose children – and their wider families – to the risk of becoming seriously ill from catching the virus and infecting others.
The “flu season” is expected to start this month yet just 2,999 children aged two and three – out of 5,244 registered with a GP surgery in Brighton and Hove – have had the vaccine.
More than 42 per cent of two and three-year-olds in Brighton and Hove remain unprotected from the risk of severe illness if they catch the flu.
The symptoms tend to come on very quickly and can be unpleasant for children, with a fever, stuffy nose, dry cough, sore throat, aching and extreme tiredness often lasting several days.
Children can also face serious complications from the flu virus, including a painful ear infection, acute bronchitis and pneumonia. Some may even need hospital treatment.
Every two and three-year-old is eligible for the flu vaccine and can have it at their family doctor’s surgery. Children in reception to year 7 were due to receive the vaccination at school.
And children of all ages with a health condition putting them at greater risk of flu are also eligible for the flu vaccine.
Dr Hildi Mitchell, head teacher at Downs Infant School in Brighton, said: “Anything we can do to help children stay well and be able to attend school is welcome.
“We encourage all our children to have the flu vaccination and our eligible school staff to be vaccinated as well.”
Brighton and Hove Clinical Commissioning Group (CCG) said: “Protecting children can also stop the flu virus spreading to other children and the family, especially babies and grandparents, who may be at higher risk from flu and who may be trying their best to stay well at this current time.”
Allison Cannon, the chief nursing officer for Sussex NHS commissioners, including the Brighton and Hove CCG, said: “We are urging parents to protect their children now from getting very ill from flu with the free flu vaccine from the NHS.”
She said: “The nasal spray vaccination is quick, effective and painless – and robust safety rules are being followed wherever and whenever vaccinations take place, whether that is at your GP practice or at your child’s school, to make sure these are being done safely to every child, parents and staff.
“Parents of two to three-year-olds who have not been vaccinated can speak to their GP practice about the arrangements this year and please attend a clinic appointment.
“Those with children in school years reception to year 7 are asked to make sure you sign their consent form to receive this through school so their children can have the flu vaccine.
“The nasal spray vaccine contains pork gelatine and if this is not suitable parents are asked to speak with their child’s nurse or doctor about options, as alternatives are available which do not contain pork gelatine.”