mRNA vaccines use mRNA made in the laboratory to teach our cells how to make a viral protein—or even a piece of the protein—that triggers an immune response inside our bodies. This immune response produces antibodies which help protect us from getting sick from that germ in the future.

First, mRNA COVID-19 vaccines are given in the upper arm muscle or upper thigh.

After vaccination, the mRNA will enter the muscle cells. Once inside, they use the cells’ machinery to produce a spike protein. The spike protein is found on the surface of the virus that causes COVID-19 infection. After the protein piece is made, our cells break down the mRNA and remove it, leaving the body as waste.

The spike protein triggers our immune system to produce antibodies and activate other immune cells to fight off what it thinks is an infection.

Through vaccination, our bodies have learned how to help protect against future infection caused by COVID-19 virus without risking potentially serious consequences from the actual COVID-19 infection.