What Is the Difference Between Immunization and Vaccination?

The terms immunization, vaccination, and inoculation are often used interchangeably, but the terms technically have different meanings. While the differences may seem semantic, using the terms correctly can help avoid misunderstandings between you and your healthcare provider.

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Vaccination and Immunization

According to the World Health Organization (WHO), vaccination and immunization are related, although one essentially describes an action while the other describes the effect. By the WHO definition:

  • Vaccination employs vaccines to stimulate the body’s own immune system to protect the person against subsequent infection or disease.
  • Immunization is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine.

Immunization confers immunity. As such, a person can become immune to a disease when the body is exposed to the disease-causing organism (pathogen) and develops antibodies to fight it. The exposure can occur either through vaccination or natural infection.

With that said, the term immunization infers vaccination rather than natural infection.

Immunization describes the actual immunological changes your body goes through after receiving a vaccine.

Inoculation and Vaccination

The Centers for Disease Control and Prevention (CDC) defines a vaccine as "a product that stimulates a person’s immune system to produce immunity to a specific disease, protecting the person from that disease."

Although inoculation and vaccination are sometimes used interchangeably, one is ultimately an act and the other is the process that spurs immunity. By definition:

  • Inoculation is the act of introducing a vaccine into a person's body. It can be used in other contexts, such as when a culture is inoculated with body fluids (such as from a nasal swab) to test for the presence of a bacterium or virus.
  • Vaccination is the process of introducing a vaccine into the body to produce immunity to a specific disease. Vaccines are usually administered through needle injections but can also be administered by mouth or sprayed into a nostril.

What Vaccines Do

Vaccination and immunization aim to protect people from potentially deadly diseases. Diseases like polio and influenza that once killed millions can now be prevented through vaccination. 

When you receive a vaccine, the immune system will recognize the substance as harmful and tailor-make antibodies designed to target that disease and that disease alone.

This is referred to as the acquired (or adaptive) immune response. The adaptive response not only attacks and neutralizes the specific pathogen but leaves behind memory cells to re-launch an attack should the pathogen return. Doing so reduces your risk of symptomatic illness should reinfection occur.

The duration of immunity can vary by the vaccine, with some wearing off relatively quickly and others providing durable protection. In cases where immunity has begun to wane, revaccination or booster shots may be needed. Tetanus is one such example.

When enough people in a community are vaccinated, it can provide protection to everyone, even those that have not been vaccinated. It does so by reducing the number of people able to spread the infection within that community, a process referred to as herd immunity.

This is how public health officials have been able to eradicate (or nearly eradicate) diseases like polio, mumps, and measles that once claimed millions of lives. When diseases aren't able to spread, they eventually die out.

Vaccine Schedules

Many parents are overwhelmed by the number of vaccines their babies need from the time of birth. While it may seem excessive to give an infant three or four shots every couple of months during the first year of life, it is during this time that babies are most vulnerable to communicable diseases.

The vaccine schedule issued by the CDC has been proven safe and effective at protecting children from common diseases that still exist in many communities. Not getting vaccinated places a child at serious risk.

If an unvaccinated child gets pertussis (whooping cough), hepatitis B, or meningococcal meningitis, the chances of severe illness and death are significantly increased.

There are also vaccines recommended for adults, such as the Zostavax and Shingrix vaccines used to prevent shingles. Booster shots may also be needed as the immune protection afforded by childhood vaccinations begin to wane.

A Word From Verywell

Vaccination, immunization, and inoculation are all essentially a part of the same process: to keep us safe from diseases that might otherwise cause us harm. Whether administered by injection, nasal spray, or orally, vaccines afford protections that almost always outweigh the potential risks.

If you are unsure whether you need a vaccine (or if a vaccine is appropriate for you), speak with your doctor or a qualified medical professional.

Vaccines Doctor Discussion Guide

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Article Sources
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