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How do mRNA Covid vaccines work?

Messenger RNA (mRNA) vaccines, such as the Pfizer/BioNTech and Moderna vaccines, were some of the first Covid-19 vaccines to receive the green light for use. How does the technology work?

This content was published on January 20, 2021 - 10:35

mRNA technology is new, but not unknown. They have been studied for a couple of decades.

Traditionally, most vaccines use weakened or inactivated versions or components of the disease-causing pathogen to stimulate the body’s immune system to create antibodies. In contrast, mRNA vaccines take advantage of the process that cells use to make proteins in order to trigger an immune response and build immunity to SARS-CoV-2, the virus that causes Covid-19.

mRNA is best described as instructions for the cell on how to make a piece of the “spike protein” that is unique to SARS-CoV-2. Since only part of the protein is made, it does not do any harm to the person vaccinated but it is antigenic.

After the piece of the spike protein is made, the cell breaks down the mRNA strand and disposes of them using enzymes in the cell. The mRNA strand never enters the cell’s nucleus or affects genetic material.

Once displayed on the cell surface, the protein or antigen causes the immune system to begin producing antibodies and activating T-cells to fight off what it thinks is an infection. These antibodies are specific to the SARS-CoV-2 virus, which means the immune system is primed to protect against future infection.

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