Messenger RNA vaccines—also called mRNA vaccines—are some of the first COVID-19 vaccines authorized for use in the United States. COVID-19 mRNA vaccines give instructions for cells to make a harmless piece of the so-called “spike protein”, which the virus uses to enter cells in the body. After the protein piece is made, the cell breaks down the instructions and gets rid of them. The immune system recognizes that the protein doesn’t belong there and begins making antibodies to protect against future infection. People who get vaccinated gain this protection without having to risk the serious consequences of getting sick with COVID-19.