Immunization vs. Vaccination

People often use the terms vaccination and immunization interchangeably, but they are technically different. Although the differences may appear semantic, correctly using the terms can help avoid any misunderstanding between patients and their doctor.

Immunization vs. Vaccination

Although immunization and vaccination are related, the World Health Organization (WHO) describes one as an action and the other as a process. Per the WHO definition:
* Vaccination – the action of using vaccines to stimulate a person’s immune system to guard them against future disease or infection.
* Immunization – the process, typically through the administration of a vaccine, where a person is made resistant or immune to a particular infectious disease.

How Do Vaccines Work?

The goal of vaccines and immunization is to guard people from potentially lethal diseases. Diseases like influenza and polio, which used to kill millions, can now be avoided with vaccines.
Upon receiving a vaccine, the body’s immune system recognizes the foreign substance as harmful and creates antibodies specific to fighting the applicable disease. This is known as the adaptive or acquired immune response. The response attacks and eliminates the specific pathogen while leaving behind memory cells that can re-launch the attack if the pathogen comes back. This helps minimize illness symptoms if reinfection occurs.

If a sufficient portion of a population is vaccinated, everyone, including those that were not vaccinated, can be protected. Known as herd immunity, it reduces the number of people that are capable of spreading the infection within the community. Herd immunity is how public health officials have eliminated, or nearly eliminated, diseases like measles, polio, and mumps that previously claimed millions of lives. If a disease is unable to spread, it will eventually die out.

Timing Vaccines and Effectiveness of Immunization

To immunize people against harmful diseases, vaccination is needed. The process starts at birth and continues later in life. The timing depends on the risk of disease at various periods of life.
Parents sometimes find the volume of vaccines their child receives from birth to be overwhelming. However, it is important to follow the recommended schedule as vaccinations are timed to guard against certain diseases when children are most susceptible to them. The Centers for Disease Control and

Prevention (CDC) have issues vaccine schedules which have been proven effective and safe at guarding children from common diseases that exist in communities. Failing to vaccinate a child places them at serious risk of disease. For example, the risk of severe illness or death from hepatitis B, pertussis, and meningococcal meningitis, are much higher for unvaccinated children compared to one that is vaccinated. There are certain vaccines, like the Shingrix vaccine that prevents shingles, that are recommended for adult patients as well.

Keep in mind that immunization is ultimately what leads to immunity. In other words, while a patient may have been vaccinated in childhood against certain diseases, it will be their level of immunization that determines how well protected they are today. How long immunity lasts can vary by vaccine with some having short lasting effectiveness while others provide long-term protection. Should immunity begin to wane, booster shots (revaccination) may be required.


Types of Immunization