Side effects of the child flu vaccine

As with all medicines, side effects of the nasal spray flu vaccine are possible, but usually mild.

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

Most children will not experience any side effects.

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, shivering, tiredness or a nosebleed.

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

They usually go away after a couple of days and you don’t need to do anything about them. Less common side effects include a slightly raised temperature, shivering or tiredness.

More information on the possible side effects of the vaccine is available in the Fluenz Tetra nasal spray suspension Influenza vaccine (live attenuated, nasal) Patient Information Leaflet.

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 years of age) if your child appears uncomfortable or unwell.

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

Remember, 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

Non-urgent advice: When to get help

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

If an infant still has a fever 48 hours after vaccination or if you're concerned about your infant’s health at any time, you should seek advice from their GP or phone NHS 24's 111 service.

The diseases that vaccines protect against are very serious and therefore vaccination should not be delayed because of concerns about post-vaccination fever.

Reporting side effects

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

This can be done by:

  • visiting the Yellow Card Scheme website
  • phoning the free Yellow Card hotline 0800 731 6789 (9.00am to 5.00pm, Monday to Friday)

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.