Vaccine Overview

Vaccines are immunization injections used to support your immune system and help prevent life-threatening or serious diseases.



Vaccines “teach” your body how to defend itself when germs, such as viruses or bacteria, invade it:

  • Exposes your body to a minor, yet safe, amount of a virus or bacteria that is dead or weakened
  • The immune system within your body then identifies and combats the infection when exposed to it in the future
  • This is a natural way of combating an infectious disease, and from this, milder infections or not getting sick is possible.

Five types of vaccines currently available:

  • mRNA vaccines directs cells to produce copies of a protein on the outside of the virus (e.g. SARS-CoV-2 coronavirus) known as the “spike protein”
  • Live virus vaccines use the attenuated, or weakened, form of a virus. For example, the varicella (chickenpox) and measles, mumps, and rubella (MMR) vaccines are both examples of this.
  • Inactivated or killed vaccines are made from a protein or other tiny part of a virus or bacteria. The Whooping cough (pertussis) vaccination is an example of this.
  • Toxoid vaccines carry a toxin or chemical made by a virus or bacteria. This makes a body more immune to negative effects of an infection, instead of the infection itself. Some examples of this are diphtheria and tetanus vaccinations.
  • Biosynthetic vaccines contain synthetic, or manmade, substances that are complementary to the makeup of a virus or bacteria. For example, the Hepatitis B vaccine is an example of this.


Shortly after birth, babies have defenses from germs caused by diseases. This defense is given by the mother through the placenta before birth. However, after a small period of time after birth, this natural protection goes away.

Vaccinating helps protect against a large amount of diseases that used were more common in the past. For example, diphtheria, polio, measles, mumps, tetanus, pertussis (whooping cough), meningitis are all less harmful because of vaccination.


Some people worry that vaccinating is unreliable or dangerous, especially for children. People hesitant on vaccination may ask their health care provider to abstain or wait to vaccinate. But the benefits of vaccinating greatly outnumber the risks.

The Centers for Disease Control and Prevention (CDC), the Institute of Medicine, and the American Academy of Pediatrics all identify that the benefits of vaccinating are greater than their risks.

Vaccines, such as the measles, mumps, rubella, chickenpox, and nasal spray flu vaccines contain live, but weakened viruses:

● People with weakened immune systems should not receive live immunizations, since they raise the chance of infection. Though, this is not the case for people with non-weakened immune systems.

● Pregnant women should not receive a live immunizations, as they can be dangerous to a fetus. A provider can inform you on the right time to receive this type of vaccination.

Vaccines used to contain a preservative called thimerosal. But now:

  • Most child and infant flu vaccinations contain no thimerosal.
  • NO commonly used vaccines for children or adults contain thimerosal.
  • Lasting research has NOT shown any correlation between thimerosal and autism or other medical issues.

However, allergic reactions are recorded, but are infrequent and mostly connected to an ingredient of the vaccine.


The US Centers for Disease Control and Prevention (CDC) sets a recommended immunization schedule every year. Talk to your provider about specific immunization information for you and your family.

You should be immunized at least one month before leaving.

Because it is needed in some countries, bring an immunization record when you travel.