Different types of COVID-19 vaccines: How they work

Curious about how mRNA vaccines and other types of COVID-19 vaccines can help you develop immunity to the COVID-19 virus? Understand how different technologies work with the immune system to provide protection.

By Mayo Clinic Staff

A coronavirus disease 2019 (COVID-19) vaccine can prevent you from getting COVID-19 or from becoming seriously ill or dying due to COVID-19. But how do the different types of COVID-19 vaccines work?

Each COVID-19 vaccine causes the immune system to create antibodies to fight COVID-19. COVID-19 vaccines use a harmless version of a spikelike structure on the surface of the COVID-19 virus called an S protein.

mRNA vaccine

Viral vector vaccine

Protein subunit vaccine

The main types of COVID-19 vaccines currently available in the U.S. or being studied include:

  • Messenger RNA (mRNA) vaccine. This type of vaccine gives your cells instructions for how to make the S protein found on the surface of the COVID-19 virus. After vaccination, your muscle cells begin making the S protein pieces and displaying them on cell surfaces. This causes your body to create antibodies. If you later become infected with the COVID-19 virus, these antibodies will fight the virus.

    Once the protein pieces are made, the cells break down the instructions and get rid of them. The mRNA in the vaccine doesn’t enter the nucleus of the cell, where DNA is kept. Both the Pfizer-BioNTech and the Moderna COVID-19 vaccines use mRNA.

  • Vector vaccine. In this type of vaccine, material from the COVID-19 virus is placed in a modified version of a different virus (viral vector). The viral vector gives your cells instructions to make copies of the COVID-19 S protein. Once your cells display the S proteins on their surfaces, your immune system responds by creating antibodies and defensive white blood cells. If you later become infected with the COVID-19 virus, the antibodies will fight the virus.

    Viral vector vaccines can't cause you to become infected with the COVID-19 virus or the viral vector virus. The Janssen/Johnson & Johnson COVID-19 vaccine is a vector vaccine. AstraZeneca and the University of Oxford also have a vector COVID-19 vaccine.

  • Protein subunit vaccine. Subunit vaccines include only the parts of a virus that best stimulate your immune system. This type of COVID-19 vaccine contains harmless S proteins. Once your immune system recognizes the S proteins, it creates antibodies and defensive white blood cells. If you later become infected with the COVID-19 virus, the antibodies will fight the virus.

    The Novavax COVID-19 vaccine is a protein subunit vaccine.

The COVID-19 vaccines available in the United States are:

  • 2023-2024 Pfizer-BioNTech COVID-19 vaccine, available for people age 6 months and older.
  • 2023-2024 Moderna COVID-19 vaccine, available for people age 6 months and older.
  • 2023-2024 Novavax COVID-19 vaccine, available for people age 12 years and older.

From Mayo Clinic to your inbox

Sign up for free and stay up to date on research advancements, health tips, current health topics, and expertise on managing health. Click here for an email preview.

To provide you with the most relevant and helpful information, and understand which information is beneficial, we may combine your email and website usage information with other information we have about you. If you are a Mayo Clinic patient, this could include protected health information. If we combine this information with your protected health information, we will treat all of that information as protected health information and will only use or disclose that information as set forth in our notice of privacy practices. You may opt-out of email communications at any time by clicking on the unsubscribe link in the e-mail.

Nov. 04, 2023 See more In-depth

See also

  1. Antibiotics: Are you misusing them?
  2. COVID-19 and vitamin D
  3. Convalescent plasma therapy
  4. Coronavirus disease 2019 (COVID-19)
  5. COVID-19: How can I protect myself?
  6. Cough
  7. Herd immunity and coronavirus
  8. COVID-19 and pets
  9. COVID-19 and your mental health
  10. COVID-19 antibody testing
  11. COVID-19, cold, allergies and the flu
  12. COVID-19 drugs: Are there any that work?
  13. Long-term effects of COVID-19
  14. COVID-19 tests
  15. COVID-19 in babies and children
  16. Coronavirus infection by race
  17. COVID-19 travel advice
  18. COVID-19 vaccine: Should I reschedule my mammogram?
  19. COVID-19 vaccines for kids: What you need to know
  20. COVID-19 vaccines
  21. COVID-19 variant
  22. COVID-19 vs. flu: Similarities and differences
  23. COVID-19: Who's at higher risk of serious symptoms?
  24. Debunking coronavirus myths
  25. Diarrhea
  26. Extracorporeal membrane oxygenation (ECMO)
  27. Fever
  28. Fever: First aid
  29. Fever treatment: Quick guide to treating a fever
  30. Fight coronavirus (COVID-19) transmission at home
  31. Honey: An effective cough remedy?
  32. How do COVID-19 antibody tests differ from diagnostic tests?
  33. How to measure your respiratory rate
  34. How to take your pulse
  35. How to take your temperature
  36. How well do face masks protect against COVID-19?
  37. Is hydroxychloroquine a treatment for COVID-19?
  38. Loss of smell
  39. Mayo Clinic Minute: You're washing your hands all wrong
  40. Mayo Clinic Minute: How dirty are common surfaces?
  41. Multisystem inflammatory syndrome in children (MIS-C)
  42. Nausea and vomiting
  43. Pregnancy and COVID-19
  44. Red eye
  45. Safe outdoor activities during the COVID-19 pandemic
  46. Safety tips for attending school during COVID-19
  47. Sex and COVID-19
  48. Shortness of breath
  49. Thermometers: Understand the options
  50. Treating COVID-19 at home
  51. Unusual symptoms of coronavirus
  52. Vaccine guidance from Mayo Clinic
  53. Watery eyes