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.
The United States’ long-standing vaccine safety program closely and constantly monitors the safety of vaccines. A critical part of the program, CDC’s Immunization Safety Office identifies possible vaccine side effects and conducts studies to determine whether health problems are caused by vaccines. Data show that the current U.S. vaccine supply is the safest in history. For more information on vaccine safety visit the CDC website.