What is a vaccine and how do they create vaccines?

Stimulate immune sys: A vaccine is supposed to stimulate your own immune system to be prepared to fight off a known infection. They can be live attenuated (injured) organsisms that cause a mild case of the disease, or they can be killed organism parts that look like live organisms. The protection is usually not permanent or complete, but it is better than nothing and usually much better than the disease.

Immune stimulants: Vaccines are proteins of the outer coat of viruses or attenuated virus which teaches your immune system to react against those proteins and combat or prevent infection of the native virus. Most are created by chemical modification of these proteins or of the actual organism which then can be safely injected to cause your own immune system to react.