Vaccines protect against serious diseases that can make you very sick and even kill you. They can also help protect the people around you, including your loved ones and strangers. Vaccines have saved millions of lives, and are responsible for wiping out some deadly infectious diseases such as smallpox and polio.
When you get a vaccine, your immune system responds to the antigen (part of a germ that causes disease) in the vaccine by making antibodies to fight it. The immune cells that make these antibodies look for the germ and “memorize” it so they can recognize and fight it again if you are ever exposed to that specific pathogen. These memory cells are very effective at preventing infection and can prevent you from getting the disease again, as long as you have the antibodies in your body.
Lab researchers work for years to identify a natural or manufactured antigen that can help the body’s immune system fight a particular germ. Once they find one, it goes through extensive lab testing and pre-clinical testing in animals before being tested on humans. It can take years for a vaccine to be developed, approved and added to the immunization schedule. CDC and the Food and Drug Administration are very careful to make sure that vaccines are safe both before they are licensed and once they are being used by the public.
For some diseases, such as tetanus (which develops from bacteria that enter the body through cuts, scrapes and dog or cat bites), your immune system can’t make antibodies naturally and you need vaccinations to help you avoid disease. Vaccines can also help you maintain immunity against diseases that can develop from common infections such as pneumonia or influenza.