There are three types of flu vaccine:
• A live attenuated quadrivalent vaccine, given as a nasal spray. This is for children and young people aged 2 to 17 years in an eligible group
• A quadrivalent injected vaccine. This is for adults aged 18 and over but below the age of 65 who are at increased risk from flu because of a long term health condition and for children 6 months and above in an eligible group who cannot receive the live attenuated vaccine
• An adjuvanted injected vaccine. This is for people aged 65 and over
Flu is unpredictable. The vaccine provides the best protection available against a virus that can cause severe illness. The most likely viruses that will cause flu are identified in advance of the flu season and vaccines are then made to match them as closely as possible. The vaccines are given in the autumn ideally before flu starts circulating. During the last ten years the vaccine has generally been a good match for the circulating strains.