How Vaccines Work

Do you know why we sometimes give you shots when you come in for your yearly check-up? If not, then keep reading to learn!

To understand how vaccines work, you’ll need a brief understanding of the immune system first: 

• Our bodies have many ways of protecting us from pathogens (germs that make us sick). Physical barriers are the first line of defense (for example, you can think of your skin as a wall around a fortress). When germs get past that barrier (think of a cut in your skin as a hole in the wall to the fortress), then the next defense against intruders is the immune system (you can think of this as the army protecting the fortress). 
   
• When germs like bacteria or a virus invade the body, they attack and multiply, which causes an infection or disease. If a germ that your body doesn’t recognize gets into your body, it can take several days for your immune system to make and use all the tools (like antibodies) needed to fight the infection. However, after the first time your body encounters that germ, it remembers how to fight it in the future and can fight it off stronger and more quickly if it ever encounters the same pathogen again.  

What are vaccines used for?

• Vaccines teach our bodies how to trigger our immune systems to protect us from germs that make us sick. This way, they can protect us from severe and potentially deadly diseases like measles, mumps, rubella, chickenpox, polio, HPV, meningitis, whooping cough, and many others. 

How do vaccines work?

• Vaccines are like a “practice run” for our bodies.
   
• If your immune system were a sports team, getting a vaccine is like having a copy of your opponent’s playbook – it tells your immune system what their plays are and how to block them. 
   
• When you get a vaccine, it teaches your immune system to produce the right type of antibodies (germ-fighting proteins) to protect you from certain diseases. Then your body takes what it learned from the vaccine so that it can be ready to protect you if you are exposed to the harmful disease-causing germs in the future.