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Do flu vaccines have any side effects?

Flu nasal spray 

After the flu nasal spray vaccination, some of the most common side effects in children and young people in the first day or two include: 

  • a runny or blocked nose 

  • reduced appetite 

  • weakness 

  • a fever 

  • a headache, and 

  • muscle aches. 

Flu vaccine injection 

If a child or young person has the flu vaccination by injection, some of the most common side effects include: 

  • pain, bruising, redness, hardness or swelling where the injection was given 

  • a headache 

  • muscle pain 

  • tiredness 

  • a change in eating habits, including loss of appetite 

  • irritability 

  • sleepiness, and

  • diarrhoea. 

Flu vaccines are very safe. 

The flu vaccine will not cause flu.

For all side effects and for more information about the vaccine, please see the relevant patient information leaflet below.

Children aged two to less than 18 years

Follow this link to the Medicines website to read more about side effects.

Children aged six months to under two years 

Follow this link to the Medicines website to read more about side effects.

Note: Children aged two to 17 years who cannot have the nasal spray vaccine, for example, due to certain health conditions or because it contains pork gelatine, may be offered the flu vaccine as an injection instead. 

Rarely, people can have a severe reaction soon after the vaccination, which causes breathing difficulties and may cause them to collapse. This is called an anaphylactic reaction, and it can also happen with other medicines and food. These reactions are extremely rare, affecting less than one in a million people. Staff who give vaccinations are trained to manage these reactions.   

People who have an anaphylactic reaction can be successfully treated and usually recover within a few hours.     

You should report suspected side effects of the vaccine online, by downloading the Yellow Card app, or by calling 0800 731 6789 (Monday to Friday, 9am to 5pm).   

Follow this link to the Yellow Card website to report any side effects.

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