Children's flu vaccine side effects

Flu vaccines for children are very safe, but like all vaccines, some children may experience side effects. The side effects linked with the flu nasal spray vaccine and flu injections are usually mild and don't last very long.

Common side effects of the flu nasal spray vaccine

The nasal spray flu vaccine has very few side effects, the main one being that children may have a slight runny nose for a short time. Other possible side effects include:

  • temperature
  • headache
  • feeling slightly unwell
  • aching muscles
  • loss of appetite

Uncommon side effects can include a rash, swollen face or nose bleed.

A mild fever following a flu vaccine is a common and expected reaction, isolation and COVID-19 testing is not usually required unless COVID-19 is suspected. Any fever after vaccination should be monitored and if you are concerned about your health at any time please seek advice from your GP or NHS Direct Wales on 0845 46 47 or NHS 111 Wales if available in your area.

Rare side effects of the flu nasal spray vaccine

As with all vaccines, there’s a very small chance of a severe allergic reaction (known medically as anaphylaxis). The overall rate of anaphylaxis after vaccination is around one in 900,000 (so slightly more common than one in a million).

Anaphylaxis is very serious but it can be treated with adrenaline. When it happens, it usually does so within a few minutes of the vaccination. Staff who give vaccinations have all been trained to spot and deal with anaphylactic reactions and children recover completely with treatment.

What to do if your child has a side effect from the flu nasal spray vaccine

If your child has a runny nose after their flu vaccination, simply wipe their nose with a tissue and then discard it (and wash your hands thoroughly).

If your child develops a fever after their flu vaccination, keep them cool by:

  • making sure they don't have too many layers of clothes or blankets on
  • giving them cool drinks

You could also give them infant paracetamol or ibuprofen to reduce their fever.

If you're worried about your child, trust your instincts and speak to your doctor or NHS 111 Wales (if available in your area) or 0845 46 47.

If your child has symptoms you think might be COVID-19 follow the current COVID-19 guidelines.

Call the doctor immediately if, you think your child has COVID-19 symptoms, or if  at any time, your child:

  • has a temperature of 39 degrees C or above, or
  • has a fit

How to report a suspected vaccine side effect

The Yellow Card Scheme allows you to report suspected side effects from a vaccine. It's run by a medicines safety watchdog called the Medicines and Healthcare products Regulatory Agency (MHRA) and it's a good way to of monitoring a vaccine's safety.

For more information visit


Click here to see all vaccination leaflets.





Last Updated: 17/02/2022 16:02:39
The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website