The flu vaccine is safe and effective. The vaccine gives the best protection against flu.
It is given to adults as an injection in the arm.
The flu vaccine 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, but it should be avoided if someone has had a serious allergic reaction to a flu vaccine in the past.
Vaccine side effects
For more information about flu vaccine side effects, visit NHS inform (external website).
Egg allergy and the vaccine
Some flu vaccines are made using eggs. An egg-free vaccine may be available for those who have an egg allergy.
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).