Some particles of a virus are introduced into your body, when you get vaccinated. These particles are just enough for your body to recognize it as an enemy virus. But it is not enough to make you sick of it. The immune system will directly start with making antibodies, which can later be stored in your adaptive immune system. The next time you get the virus in your body, your body recognize the virus and kills it. For example, a vaccination helps your body to protect itself against viruses.
Watch the video to learn more about the different types of vaccines.