COVID-19 Vaccination: Key Terms to Understand

Words to help you stay informed, take precautions, and make good decisions regarding your own health and safety.

Understanding basic information regarding vaccines can help you stay informed, take precautions, and make good decisions regarding your own health and safety.

COVID-19 is an infectious disease first identified in 2019. Caused by the SARS-CoV-2 virus that affects the respiratory system, COVID-19 is easily spread from person to person through infected droplets that come into contact with the eyes, nose, or mouth through a cough or sneeze.

The COVID-19 virus has spread throughout the world, affecting millions of people. The symptoms include fever, cough, shortness of breath, body aches, chills, loss of taste and/or smell, fatigue, and headaches. Symptoms can be mild to severe, and some infected people have no symptoms.

Since vaccines are available, it is important to understand information regarding those vaccines so you can stay informed, take precautions, and make good decisions regarding your own health and safety.

This article will discuss terms related to the COVID-19 vaccines.

  • Vaccine. A vaccine is a simple and safe way to protect your body from infections. Vaccines teach our immune systems to create antibodies, protecting and preparing our bodies from future infections without us having to get the illness.
  • Immunization. Immunization is the process through which you become protected from certain diseases by means of vaccination.
  • Immunity. Your immune system protects your body from disease through immunity. Natural immunity occurs when you have already been infected by a disease and your body produces antibodies. Vaccine-induced immunity occurs when the virus is introduced to your body through a vaccine.
  • Herd immunity. Herd immunity happens when a large percentage of the population becomes immune to a disease, which means it will not spread as easily. Herd immunity can help protect those who are unable to be immunized or fully immunized, such as people who are immunocompromised and people in an age group where there is no available vaccine.
  • Emergency use authorization (EUA). In situations like a global pandemic, emergency use authorization allows medical countermeasures—such as vaccines—to be used, even though they may not be officially approved by the Food and Drug Administration (FDA). This is done because the benefits outweigh the risks. The FDA can grant EUA to vaccinations if there are no fully approved alternative treatments available.
  • Antibody. Antibodies are proteins in the immune system that attach themselves to disease-causing agents, like viruses. This helps the immune system identify and destroy the disease-causing agent.
  • mRNA vaccine. These vaccines teach your immune system how to create a spike protein. This triggers an immune response which produces antibodies that fight the coronavirus that causes COVID-19. The Moderna and Pfizer vaccines are both mRNA vaccines.
  • Carrier vaccine. Also called a viral vector vaccine. This type of vaccine uses a modified, harmless virus to deliver spike protein DNA into cells in the body. The cells begin making spike proteins, and the immune system begins making antibodies that target the spike protein—and protect against COVID-19. The Johnson & Johnson vaccine is a carrier vaccine.
  • Protein adjuvant. This type of vaccine contains a spike protein plus an adjuvant (an ingredient that helps boost your immune response). The spike protein on its own does not cause infection, but it does cause the immune system to make antibodies against COVID-19. The vaccine being manufactured by Novavax is a protein adjuvant vaccine.
  • “Mix and match.” The FDA and CDC have declared it is safe to “mix and match” vaccines and boosters. For example, if your first two doses were Moderna, you can safely get a Pfizer booster. Or if you initially received the J&J vaccine, you can safely get a Moderna or Pfizer booster. If you have any concerns about vaccines or boosters, your best source of information will be a healthcare provider.
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World Health Organization. "Coronavirus disease (COVID-19)."
Centers for Disease Control and Prevention. "COVID-19 Overview and Infection Prevention and Control Priorities in non-U.S. Healthcare Settings."
UpToDate. "COVID-19: Epidemiology, virology, and prevention."
Johns Hopkins Medicine. "What is Coronavirus?"
World Health Organization. "Vaccines and immunization: What is vaccination?"
Centers for Disease Control and Prevention. "Immunization: The Basics."
Johns Hopkins Medicine. "COVID Natural Immunity: What You Need to Know."
Mayo Clinic. "Herd immunity and COVID-19 (coronavirus): What you need to know."
U.S. Food & Drug Administration. "Emergency Use Authorization for Vaccines Explained."
Tia Ghose. "What are antibodies?" LiveScience. July 17, 2020.
Centers for Disease Control and Prevention. "Understanding mRNA COVID-19 Vaccines."
Kathy Katella. "Comparing the COVID-19 Vaccines: How Are They Different?" Yale Medicine. February 25, 2022.
Nebraska Medicine. "Moths and tree bark: How the Novavax vaccine works."
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