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 preparation that is used to stimulate the body’s immune response against diseases. Vaccines are usually administered through needle injections, but some can be administered by mouth or sprayed into the nose.

Vaccination: The act of introducing a vaccine into the body to produce protection from 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: September 1, 2021