Vaccinations How Vaccines Work

Many people know that vaccinations aim to help protect individuals from certain diseases, but most don’t really know how vaccinations work. Understanding how vaccines work can help you appreciate how important they are — for both you and your children.

The Science Behind Vaccination

When a person gets a disease, his immune system produces antibodies to fight that disease, which can take some time. In the meantime, sickness occurs that only goes away when the antibodies begin fighting the disease.

However, if the person gets the same disease again, his antibodies will begin to fight the disease faster. The immune system has a kind of memory and won’t have to start from scratch when producing antibodies a second time.

Vaccinations introduce a dead or weakened form of a disease into the body. Ideally, the immune system can recognize the disease and create antibodies for the weakened disease. Because the disease isn’t at its strongest, you usually won’t get sick from it. if you contract a stronger form later, however, your immune system will recognize it and be able to produce antibodies to fight it off.

Types of Vaccines

Vaccinations that aim to fight off disease come in four forms:

  • Altered live bacteria or viruses that can no longer cause disease: Chemicals, such as formaldehyde, inactivate bacteria and viruses.
  • Dead bacteria or viruses: Dead cells can no longer infect a person, but will create an immune response.
  • Parts or portions of bacteria or viruses: Antibodies can form against part of the bacteria or virus. Some of the newest vaccines, including hepatitis A and hepatitis B, fall in this category.
  • Toxoids, or toxins from bacteria that have been altered to be harmless: Toxoids are treated with heat or chemicals, such as formalin, to inactivate them. Tetanus and diphtheria vaccines fall under this category.

Another type of vaccine, called a live attenuated vaccine, consists of a naturally occurring germ. This type of vaccine can cause a slight infection, but won’t cause a serious occurrence of the disease. Live attenuated vaccines include:

  • Measles vaccine
  • Mumps vaccine
  • Oral polio vaccine
  • Rubella vaccine
  • Varicella vaccine (also known as chicken pox vaccine).

Re-Vaccination and “Boosters”

In some cases, vaccines may need to be re-administered after a certain period of time. These are sometimes called “booster” shots or re-vaccinations.

Children are vaccinated against certain diseases at infancy, before elementary school and before college. Adults very seldomly require boosters, but re-vaccination may be necessary before entering a foreign country or beginning certain types of work.


Maybury Okonek, B. A.