How does a vaccine work

To put it in smaller words: a vaccine is a small dose of the virus so your body gets used to the small dose and then can fight off the larger virus when it's being spread around

Vaccines are like a training course for the immune system. They prepare the body to fight disease without exposing it to disease symptoms. When foreign invaders such as bacteria or viruses enter the body, immune cells called lymphocytes respond by producing antibodies, which are protein molecules.