How does vaccination protect us from disease?

How does vaccination protect us from disease?
Ans: Vaccines protect us from diseases by preparing our immune system to recognize and fight serious, and sometimes deadly, diseases. A vaccine contains a specific part of a germ (bacteria or virus), called an antigen. The antigen is killed or disabled before it's used to make the vaccine, so it can't make us sick. Vaccines, and the antigens they contain, stimulate our immune system's B cells to develop protective substances called antibodies. These antibodies are responsible for killing germs that enter our body. Once activated, B cells can stay in our body for a lifetime and allow our body to remember the germ that stimulated their creation. Throughout our life, these cells will recognize and fight the actual disease caused by the germ when and if we come into contact with it.