Immunization: The Basics

Understanding mRNA COVID-19 Vaccines

mRNA vaccines are a new type of vaccine to protect against infectious diseases. Learn about how COVID-19 mRNA vaccines work.

Definition of Terms

Immunity: Protection from an infectious disease. If you are immune to a disease, you can be exposed to it without becoming infected.

Vaccine: A product that stimulates a person’s immune system to produce immunity to a specific disease, protecting the person from that disease. Vaccines are usually administered through needle injections, but can also be administered by mouth or sprayed into the nose.

Vaccination: The act of introducing a vaccine into the body to produce immunity to a specific disease.

Immunization: A process by which a person becomes protected against a disease through vaccination. This term is often used interchangeably with vaccination or inoculation.

Page last reviewed: May 16, 2018