Conventional vaccines like influenza, shingles, and pneumonia vaccines usually contain either an inactivated portion of a virus, a live viral vector, a protein subunit, or a virus-like particle. These are all considered antigens, which are recognized by the body as an infectious agent. By doing so, these vaccines stimulate the body’s immune system to fight the infectious agent and be ready to provide a more rapid response if exposed to it again in the future. 

Unlike normal vaccines, an mRNA vaccine works by using your body’s existing machinery: the cell’s processes of making DNA, RNA, and eventually proteins! Rather than injecting a protein into the body, the vaccine inserts a messenger RNA (mRNA) sequence (the genetic sequence that contains directions for what molecules to build) which is coded to produce only a fragment of the disease-specific antigen for the SARS-CoV-2 virus.

Once produced within the body, the antigen will be recognized by your immune system, preparing it to fight the real virus if it is exposed to it in the future, without causing the actual disease. The body does this by making their own proteins, called antibodies, that can neutralize the antigen and the real virus if you ever get infected. Your body will also make memory cells that can produce antibodies at a much faster rate during future exposures.

Each person will require two doses of the Pfizer or Moderna vaccine. Two doses allows your body the chance to produce more immune-system barriers against the virus.