Vaccines train your immune system to create antibodies, just as it does when it is exposed to a disease.

When you get a vaccine, your immune system responds. It:

  • recognises the invading germ, such as the virus or bacteria
  • produces antibodies. Antibodies are proteins produced naturally by the immune system to fight disease
  • remembers the disease and how to fight it.

If you are then exposed to the germ in the future, your immune system can quickly destroy it before you become unwell.

However, because vaccines contain only killed or weakened forms of germs like viruses or bacteria, they do not cause the disease or put you at risk of its complications.