Immunizations are an important part of taking care of yourself and staying healthy. Without immunizations, many more people would get sick or even die earlier. Today, immunizations are a common part of life, and most people take them for granted. Even though most people get immunizations throughout their life, many people-kids and adults-don't understand much about how immunizations work. What happens when you get a shot? How do immunizations keep you healthy? How did people first think of immunizations as a way to keep people from getting sick? You'll find answers to all of these questions and more