For instance, when we catch chickenpox we make antibodies. We will be sick now, but won't get chickenpox when we grow up. But some infectious diseases are very dangerous, such as tetanus, measles or diptheria. We must build immunity to them without getting sick first. That's when a vaccine is used.
Some vaccines provide lifelong protection.
Other vaccines, like tetanus and diptheria vaccines, require a booster shot every 10 years to keep the antibodies strong and ready to fight. All rights reserved.