Types of Ingredients:

  • Active ingredients: the substances that trigger your immune system to make antibodies. These ingredients are often derived from the pathogen itself. There are multiple types of active ingredients depending on the type of vaccine

  • Adjuvants: a compound added to some vaccines to strengthen the immune response

  • Antibiotics: substances that kill bacteria or prevent them from dividing. Antibiotics are used in some vaccines to prevent contamination during the manufacturing process

  • Carbohydrates: This is another word for sugar. Carbohydrates are normally used as stabilizers in vaccines

  • Lipids: substances that do not mix with water such as fats, hormones, waxes, and oils

  • Salts: a type of compound that can act as electrolytes, which are charged substances that help to maintain the pH and fluid balance in the body so that the organs can function properly. Some common examples of electrolytes are sodium (Na+), potassium (K+), and chloride (Cl-). NaCl (table salt) is a common example of a salt.

Types of Vaccines

Attenuated Vaccines: 

Contain a weakened version of the bacterium or virus that is unable to cause disease in healthy people. These vaccines tend to be very effective at creating a strong immune response 

Some examples of attenuated vaccines include the measles, mumps, and rubella (MMR) combined vaccine, the rotavirus vaccines, the nasal flu vaccine (flumist), and the chickenpox vaccine.

Inactive Vaccines: 

Contain a version of the whole bacterium or virus that is dead or cannot replicate. This type of vaccine cannot cause disease even in people with very weak immune systems. 

Some examples of inactive vaccines are the hepatitis A, influenza (flu), and polio (IPV) vaccines.

Subunit Vaccines:

Made to create an immune response to a specific piece of a bacterium or virus such as a protein or sugar. Subunit vaccines create a strong immune response and can usually be given to people who are immunocompromised, but please check with your doctor. 
Examples of subunit vaccines include hepatitis B, HPV, meningococcal, meningococcal B, Haemophilus influenzae type B (Hib), pneumococcal, tetanus, diphtheria, and pertussis.

Nucleic Acid Vaccines:

mRNA is a type of genetic information that is used to make a protein. In the vaccine, the mRNA is used to make a bacterial or viral protein. The mRNA and protein are harmless on their own. The immune system responds to this protein by creating antibodies. The mRNA encodes a protein that teaches your body how to respond if it is exposed to the virus in the future.
Some examples of nucleic acid vaccines are the Pfizer and Moderna COVID-19 vaccine

Viral Vector Vaccines:

Viral vector vaccines use a modified virus that is harmless in order to deliver the genetic information to make a bacterial or viral protein. The immune system responds to this protein by creating antibodies, which teach your body how to respond if it is exposed to the virus in the future. Some examples of viral vector vaccines are the Johnson & Johnson and Novavax COVID-19 vaccines.

For a good explanation of these vaccines, click here.

Relevant Terms

  • Antibody: a protein made by the immune system in response to a foreign particle (antigen). These proteins circulate in the blood and help defend the body against the substance.  

  • Antigen: This is any substance that triggers the immune system to create antibodies. For example, allergens such as pollen are antigens. 

  • Bacterium: the singular of bacteria (one bacterium, two bacteria)

  • mRNA: Messenger ribonucleic acid (mRNA) is a form of genetic material that acts as a template to make proteins.

  • Pathogen: a microscopic organism that can cause disease (usually a bacterium or virus)

  • pH: a measure of how acidic or basic a solution is. The scale ranges from 0 (very acidic) to 14 (very basic). A pH of 7 is neutral.

  • Quadrivalent: Protects against four different versions of the pathogen (in this case, influenza virus)

  • Viral vector: a version of a virus that cannot replicate or cause disease. It is used to deliver genetic information so that the body can make a protein that acts as an antigen.