Yes, I believe in vaccine too. But this is because we were educated from young about them. However it doesn't means human can't live without vaccine. Look at our grandfathers and older generation. They have been living fine without vaccines. And some who even believe vaccines are doing more harm than good. One point to think about it that the modern medicines and vaccines could possibly be the reason that causes other type of diseases. And because of that, more and more medicines become available. People created B medicine to cure A disease but it causes C disease. So you need D medicine to cure C disease now along with needing medicine A. You see where I am going with this? Human body naturally is able to fight diseases. The body can adapt to new type of disease over time. However, due to the help of medicine, you body does not need to work that hard anymore. Therefore, you become dependent on medicine to cure common flu. When people in the older days just need to drink some chicken soup and so on.