That disease was smallpox, one of the most devastating diseases in the world, and was declared eradicated in 1980 (smallpox). This and all the other reasons should be proof enough that vaccination is a great thing. It's true that you may believe that vaccines can cause autism spectrum disorder (ASD), cancer, and other scary things. Yet it is true that these beliefs are wrong and have been proven wrong. Some people believe that some preservatives and vaccine ingredients cause these disorders, but this is not the case. It is as the CDC states: “…some people have also had concerns about other vaccine ingredients in relation to ASD. However, no link has been found between vaccine ingredients and ASD.” (Vaccines do not cause autism.) Vaccination is a good thing because it keeps us healthy, it does so safely, and it can eradicate diseases that would otherwise decimate the human race. Vaccines keep us safe and healthy and will continue to do so if we continue to get vaccinated. To people who are against vaccines because of what others say, there are some side effects that are actually worth avoiding if they prevent protection from possibly more serious disease due to not being administered