The flu vaccine is safe and effective. It gives the best protection against flu.

The vaccine is given to adults as an injection in the upper arm.

It contains no live viruses and cannot give someone the flu.

Like all medicines, it can cause side effects, which are usually mild.

If adults have questions about the vaccine, you can signpost them to the NHS inform flu vaccine pages (external website).

Most adults can have the flu vaccine, unless:

• they’ve had a serious allergic reaction (anaphylaxis) to a flu vaccine in the past
• if they’re allergic to any of the vaccine ingredients

Vaccine side effects

For more information about flu vaccine side effects, visit NHS inform (external website).

Vaccine safety

All medicines (including vaccines) are tested for safety and effectiveness before they're allowed to be used.

Once they're in use, the safety of vaccines continues to be monitored by the Medicines and Healthcare products Regulatory Agency (MHRA).