Question

"Even though vaccines contain a pathogen, a person who has received a vaccine usually does not get sick. Why not?"
Please help! I am so confused!

Answer 1

the pathogen has been disabled, so it cannot grow and infect the patient. The body recognizes it as a pathogen, however, so it produces antibodies to prevent infection when a live germ is encountered later on.

Answer 2

Thank You sooooooo much for your help @oobleck !