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Flu vaccine side effects

Flu vaccines are very safe.

All medicines can have side effects and side effects after a flu vaccine are usually very mild and only last for a day or so.

The most common side effects from a flu injection are a sore arm, mild fever or slight muscle aches. aTIV one of the flu vaccines for best protection in older people is more likely to cause a sore arm

If you have a sore arm after the vaccination, try these tips to ease it:

  • continue to move your arm regularly
  • use a heat pack or warm compress on the area
  • use an ice pack on the area if it becomes hot and sore – do not apply ice directly to your skin: wrap it in a towel first
  • take a painkiller, such as paracetamol or ibuprofen – do not give aspirin to children under 16

After the nasal spray flu vaccine some children may get a temperature, feel tired, have a headache, aching muscles or reduced appetite for a day or two after having a flu vaccine. The nasal spray may also cause a runny or blocked nose.

The flu vaccine will not cause flu.

If you have what you think is flu after vaccination, it may be that you have caught a flu-like illness that isn't really flu, or you may have caught flu before your flu vaccination had taken effect. Protection usually starts 10-14 days after the flu vaccination.

Allergic reactions to a flu vaccine

Serious allergic reactions (anaphylaxis) to flu vaccines are very rare. Healthcare staff giving vaccinations are fully trained to deal with anaphylaxis, and with prompt treatment, individuals make a quick and complete recovery.

Contact your GP surgery or community pharmacist if you experience severe side effects that are not improving over time.

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.


Click here to see all vaccination leaflets.

Last Updated: 11/11/2019 13:11:33
The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website