Q: How does a vaccine work?
A: When you receive a vaccine, the specific defense of the immune system is exposed to the antigens of the pathogen you are to be protected against. Memory T and B-cells are produced so that your body can quickly recognize and fight against the pathogen if it ever enters and attacks your body. Basically, the vaccine simulates exposure to the pathogen, by presenting a harmless weakened version. In the same way that a fire drill gives people a safe way to practice getting out of a dangerous situation, the vaccine gives a safe way for the body to practice recognizing and fighting the real pathogen right away if the body is ever exposed to it.


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