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Vaccine Types—COVID-19 Vaccines

When deciding to get a COVID-19 vaccine, it may help to understand the different vaccine technologies available. At least 40 vaccines against the SARS-CoV-2 virus (the cause of COVID-19 illness) are approved or authorized for use in at least 197 countries around the world. These vaccines have gone through extensive testing prior to government approval.

All of the COVID-19 vaccines can be grouped into categories based on how they are designed, including what is in them and how they teach your body to build immunity to the SARS-CoV-2 virus. These categories are also called vaccine technologies or vaccine platforms.

MYTH: The vaccines cause viral shedding or make you sick with COVID-19.

FACT: Vaccines that do not contain live viruses can’t cause viral illness. They can’t make you contagious or cause viral shedding, either.

mRNA Vaccines

The mRNA vaccines contain a piece of messenger ribonucleic acid (mRNA). The mRNA provides instructions for your cells to produce a harmless piece of protein found on the SARS-CoV-2 virus, called the spike protein. After following the instructions, your body breaks down the mRNA and removes it as waste. Once your cells produce the spike protein, the immune system can recognize this protein as something that does not belong. The immune system then activates to remove the protein and to build memory cells that can recognize the protein in the future. If you are subsequently exposed to the SARS-CoV-2 virus, your body’s immune system will recognize the spike protein and attack the virus.

The mRNA vaccine platform has been well studied.

Protein Subunit Vaccines
Viral Vector Vaccines

Viral vector vaccines contain a “vector virus.” A vector virus is a harmless version of a virus that has been modified so that it can’t replicate itself, infect you with the virus, or spread to other people. The vector virus does NOT cause COVID-19. When the vaccine is injected into the muscle, the harmless vector virus enters your cells. It acts like a delivery system bringing instructions for your cells to produce a harmless piece of protein found on the SARS-CoV-2 virus, called the spike protein. Your immune system recognizes this spike protein as something that does not belong. The immune system then activates to remove the protein and to build memory cells that can recognize the protein in the future. Your body breaks down the viral vector and removes it as waste. If you are subsequently exposed to the SARS-CoV-2 virus, your body’s immune system will recognize the spike protein and attack the virus.

Similar to the mRNA-based vaccine platform, viral vector vaccine platforms have been well studied.

Protein Subunit Vaccines
MYTH: The vaccine will alter my DNA.

FACT: None of the vaccines can alter your DNA in any way. To learn more, visit the CDC.

Your body breaks down and removes the mRNA, viral vector, viral protein, or DNA from the vaccine as waste.

Protein Subunit Vaccines

Protein subunit vaccines contain a small harmless piece of the virus. This piece is a protein found on the SARS-CoV-2 virus called the spike protein. When the vaccine is injected into the muscle, the immune system can recognize this spike protein as something that does not belong. The immune system then activates to remove the protein and to build memory cells that can recognize the protein in the future. If you are subsequently exposed to the SARS-CoV-2 virus, your body’s immune system can recognize the spike protein and attack the virus.

Protein subunit vaccines may also sometimes contain an adjuvant. An adjuvant is an ingredient added to the vaccine to help create a stronger immune response for the person being vaccinated. Adjuvants have been used in vaccines for more than 70 years.

Protein Subunit Vaccines