Side effects of the child flu vaccine

Like all medicines, the nasal spray flu vaccine can cause side effects. They're usually mild and short term, and not everyone gets them. Side effects usually go away after a couple of days and you do not need to do anything about them.

These potential side effects are much less serious than flu or complications associated with flu.

Common side effects from the nasal spray

If your child had the nasal (nose) spray vaccine, the most common side effects are:

  • headache
  • muscle aches
  • a blocked or runny nose
  • reduced appetite
  • weakness

Less common side effects include a slightly raised temperature (temperature above 38°C), shivering, tiredness, or a nosebleed after the nasal spray flu vaccine.

More information on the possible side effects are available in the patient information leaflet for the:

Common side effects from the injection

If your child had the injectable vaccine, they might experience similar side effects to the nasal (nose) spray vaccine except the blocked or runny nose.

The most common side effects are at the site where the injection was given:

  • swelling
  • redness
  • heavy feeling or tenderness
  • a small hard lump

Fever after the vaccine

A fever is a body temperature of 38°C or above. Fevers are quite common in young children, but are usually mild. If your child’s face feels hot to the touch and they look red or flushed, they may have a fever. You can check their body temperature with a thermometer.

Keep your child cool by:

  • making sure they do not have too many layers of clothes or blankets on
  • turning down the heating in your home
  • giving them plenty of cool drinks

Putting your child in a bath, sponging them down or fanning them will not lower their fever but it might comfort them.

As fevers are usually mild, you only need to give a dose of paracetamol (or infant paracetamol if your child is under 6) if your child appears uncomfortable or unwell.

Ibuprofen can be used to treat a fever and other post-vaccination reactions. Giving ibuprofen at the time of vaccination to prevent a fever is not effective.

Never give medicines that contain aspirin to children under 16.

Always read the instructions on the bottle or packet very carefully.

More about treating a fever in children.

Urgent advice: Speak to your GP or phone 111 if:

  • an infant still has a fever 48 hours after vaccination
  • you're concerned about your infant’s health at any time

If you're worried about your child, trust your instincts.

Reporting side effects

You can report suspected side effects of vaccines and medicines through the Yellow Card Scheme.

This can be done by:

If you’re unsure about anything, or have any questions about the child flu vaccine, speak to your health or immunisation team, practice nurse or GP.

Last updated:
11 August 2022

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