Immunization: The Basics

Definition of Terms

Let’s start by defining several basic 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.

Links to Basic Immunization Information

  • Why immunize?
    Learn how getting vaccinated can protect your grandchildren, prevent epidemics, and eliminate diseases and their serious consequences.
  • Brief overview of adult and childhood vaccine-preventable diseases and vaccines
    Read about the serious diseases that cause long-term illnesses, hospitalization, and even death, and which can be prevented by vaccines.
  • 10 things a parent should know about immunizations
    Includes how many vaccine doses your child needs, the importance of keeping records, side effects, etc.
  • How immunity works: types of immunity
    Learn the difference between the two basic types of immunity: active and passive.
  • Common questions
    Find answers to common questions about immunization.
  • What would happen if we stopped vaccinations?
    See how diseases that are rare today could once again become common—and deadly—if vaccination coverage does not continue at high levels.
  • Life-cycle of an immunization program
    See how a successful immunization program can lead to a temporary increase in disease. Follow the evolution of a disease, from a time when there was no vaccine untilit is eradicated.

Related Information and Materials

  • The Parents’ Guide to Childhood Immunizations
    68-page booklet introducing parents to all childhood diseases and the vaccines that can protect children from them
  • The Vaccines for Children Program
    The Vaccines for Children (VFC) Program offers vaccines at no cost for eligible children through VFC-enrolled doctors. Find out if your child qualifies. Vaccinating on time means healthier children, families and communities.

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Page last reviewed: May 16, 2018