How do mRNA vaccines work?

Before we can learn how the mRNA vaccine works,  let's first learn how mRNA is used in your body cells. Our bodies are made of millions of cells  cells are like little factories that make the thousands of proteins we need to survive. These are muscle cells. They have fibers made of proteins that help muscles do their job but how do these proteins get made? Let's look inside the cell. As we enter inside the cell, we see a  busy place with constant activity.   The nucleus is the control center of the cell and  where all of the information to grow and divide   is stored in these long curly strands called DNA.   DNA is stored in this twisted ladder with  each strand carrying the information to make  many different proteins. To make a protein the strands of the DNA must be unwound and copied into a temporary message called mRNA.   Outside the nucleus proteins are  built using the mRNA's instructions.   The mRNA itself is unstable and  doesn't hang around the cell forever,   only as long as a protein needs to be made. Once made proteins can stay inside this muscle cell   or they can travel outside the cell depending  on where they are needed. This protein is just one example of the thousands of proteins made by all your cells in order to keep you alive.   Scientists have designed mRNA molecules that  utilize your cell's protein making machinery   to train your body to fight off viruses. This is the virus that causes COVID-19. It is covered in spike proteins. These proteins allow the virus to lock onto and infect our cells. To develop the vaccine, scientists drew on decades of prior research.  They first designed an mRNA molecule to just one part of the spike protein which cannot give you COVID-19. mRNA is fragile to get it safely into your cells, scientists put mRNA into a protective layer of fat. One dose of the mRNA vaccine contains many of these spike mRNA molecules that bind to and are absorbed by cells in the body.   Once inside the spike mRNA is treated just  like any other mRNA message in our cells. The protein-building machinery reads mRNA and builds  the part of the viral spike protein encoded by the mRNA vaccine. Pieces of the spike protein travel to the surface of the cell where they're recognized by the immune system. The spike mRNA  message is unstable and is eventually destroyed.   The immune system activates the immune response by  sending out warning signals. Antibodies and immune cells roam around your body on the lookout for the spike protein, but over time the immune system becomes less alert to the spike protein.   When another dose of the vaccine is given, the process   is repeated and the immune system is boosted  and back on the alert for viral spike proteins.   Longer lasting immune cells build a memory of the  spike protein to recognize the virus faster and more efficiently. This quick recognition of the virus makes any illness less severe in people who are vaccinated. Now, if a patient is infected with  a virus that causes COVID-19, the body's immune   cells quickly recognizes spike proteins of an invading virus. When this happens the immune cells trigger a large immune response and successfully fight off infection and prevent severe illness. [Music]

Channel: SEP Fred Hutch

Views: 96,007

Keywords: science, COVID-19, COVID, SARS-CoV-2, mRNA, proteins, vaccine hesistancy

Id: Be4GLTiawrQ

Length: 4min 11sec (251 seconds)

Published: Mon Dec 05 2022