How do vaccines work?

Vaccines work by training your immune system to recognize and fight the virus or bacteria when it comes in contact with your body. They help you fight disease without you getting extremely sick. 

Our immune systems are designed to remember. Once exposed to one or more doses of a vaccine, we typically remain protected against a disease for years, decades or even a lifetime. This is what makes vaccines so effective. Rather than treating a disease after it occurs, vaccines prevent us in the first instance from getting sick. World Health Organization

Can I get the disease from the vaccine?

No. Vaccines train your immune system to create antibodies, just as it does when it’s exposed to a disease. However, because vaccines contain only killed or weakened forms of germs like viruses or bacteria, they do not cause the disease or put you at risk of its complications. World Health Organization

Well, what's in a vaccine?

All the ingredients and the vaccine itself are rigorously tested and monitored for safety. The ingredients all have a specific purpose. World Health Organization

• Antigen is a killed or weakened form of the virus or bacteria. It goes to work training our body what to look for and how to fight off the disease.
• Adjuvants help boost our immune response, so vaccines work better. 
• Preservatives ensure a vaccine stays effective.
• Stabilizers protect the vaccine during storage and transportation.

I know kids get vaccinations, but are vaccines harmful to adults?

We know that childhood vaccines save over 4 million lives every year. They also save adults, but there are some cautions. Some people with medical conditions should wait before getting vaccinations, including:

• Those with chronic illnesses or treatments (like chemotherapy) that affect the immune system;
• Those with severe and life-threatening allergies to vaccine ingredients, which are very rare;
• Those with severe illness and a high fever on the day of vaccination.  World Health Organization

Every authorized or approved vaccine goes through safety testing, including:

• Testing and evaluation of the vaccine before it’s licensed by the Food and Drug Administration (FDA) and recommended for use by the Centers for Disease Control and Prevention (CDC)
• Monitoring the vaccine’s safety after it is recommended for infants, children, or adults