protect individuals and populations against disease
What do the antigens that vaccines contain do?
They cause the body to produce memory cells against a particular pathogen, without the pathogen causing disease
This means you become immune without getting any symptoms
What do vaccines do?
protect individuals that have them because they reduce the occurrence of the disease, those not vaccinated are also less likely to catch the disease because there are fewer people to catch it from. THIS IS HERD IMMUNITY
What do vaccines ALWAYS contain?
Antigens - these may be free or attached to a dead of attenuated (weakened) pathogen
what is an attenuated pathogen?
a weakened pathogen
What are sometimes given later on (eg after several years)?
booster vaccines- to make sure that memory cells are produced
