Q: How do vaccines work?
A: Vaccines usually contain a small amount of the organism that causes an infection. In general, the vaccine contains just enough of the organism to help your body defend against the infection, but not enough to make you sick. In this way, vaccinations allow you to become immune to an infection without having the illness first.
There are two kinds of vaccines:
- Those that contain a live organism
- Those that contain an organism that has been inactivated
Generally, live-virus vaccines are not recommended for pregnant women.