How Vaccines Work
SARS-CoV-2 is the virus that causes COVID-19. The spike protein on the surface of SARS-CoV-2 is an example of an antigen.
Vaccines are the best way to train our immune system to recognize viruses, or pieces of viruses, called antigens. Our immune system creates antibodies and other defenses to protect us.
When a vaccinated person is exposed to SARS-CoV-2, their immune system will recognize the viral antigens and spring into action to keep them healthy. There are many different types of vaccines, as seen in the diagram above.
Types of Vaccine Platforms
All vaccine platforms are designed to train our immune system. There are two categories of COVID-19 Vaccines: Component Viral Vaccines and Whole Virus Vaccines.
Component Viral Vaccines
- Protein Subunit: Contains isolated and purified viral proteins
- Virus-like Particles (VLP): Contains viral proteins that mimic the structure of the virus, but no genetic material
- DNA-based and RNA-based: Contains viral genetic material (such as mRNA) which provides the instructions for making viral proteins
- Non-Replicated Viral Vector: Contains viral genetic material packaged inside another harmless virus that cannot copy itself
- Replicating Viral Vector: Contains viral genetic material packaged inside another harmless virus that can copy itself
Whole Virus Vaccines
- Inactivated: Contains copies of the virus that have been killed (inactivated)
- Live-Attenuated: Contains copies of the virus that have been weakened (attenuated)