mRNA vaccines have strands of genetic material called mRNA inside a special coating. That coating protects the mRNA from enzymes in the body that would otherwise break it down.
It also helps the mRNA enter the dendritic cells and macrophages in the lymph node cells near the vaccination site.mRNA can most easily be 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 vaccinated person, but it is antigenic.After the piece of the spike protein is made, the cell breaks down the mRNA strand and disposes of it using enzymes in the cell.