Side effects of the flu vaccine

Like all medicines, the flu vaccine can cause side effects. They're usually mild and normally last only a day or two. It’s normal to experience side effects after a vaccine. It shows the vaccine is teaching your body’s immune system how to protect itself from the disease. But not everyone gets side effects.

Side effects are usually mild and may include:

  • tenderness, swelling and/or redness at the site of the injection
  • headache
  • muscle aches
  • fever (temperature 38°C or above)

You may also feel generally unwell. These common side effects are much less serious than developing flu or complications associated with flu, and they usually go away within a few days.

You can rest and take the normal dose of paracetamol (follow the advice in the packaging) to help make yourself feel better.

Urgent advice: Phone 111 if:

You're concerned about yourself or anyone else in your household who is unwell following a vaccination.

Where can I report suspected 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
  • using the Yellow Card app
  • phoning the Yellow Card hotline 0800 731 6789

More information about vaccine side effects

More information on the possible side effects of the flu vaccine is available in the patient information leaflets.

Last updated:
07 August 2023