How Do mRNA Vaccines Work?

Dr. Paul Offit explains how COVID-19 vaccines based on messenger RNA technology work.


How do mRNA vaccines work?

Paul Offit, MD: Hi, my name is Paul Offit, talking to you from the Vaccine Education Center at the Children's Hospital of Philadelphia. It looks like that regarding vaccines that are going to be directed against the disease COVID-19, probably the first couple that come out are going to be so-called mRNA vaccines, which just stands for messenger RNA.

So how does that work? The good news I get about this vaccine is that we know the protein that comprises the virus that we're interested in; it's that protein that sits on the surface of the virus, that emanates from the surface of the virus, like a spike, and that's the protein that's responsible for attaching the virus to cells. But, if you can prevent the virus from attaching to cells, you can prevent the virus from infecting cells. We also know the gene that makes that protein. The gene is called messenger RNA. Messenger RNA is the gene that eventually is translated to become a protein. We all have messenger RNA in our body because we make proteins all the time. And usually, the messenger RNA after it makes that protein degrades relatively rapidly.

So, the way this is going to work, the mRNA vaccines, is it’s the mRNA that codes for that coronavirus spike protein; you're inoculated with that small, little piece of genetic material; that genetic material then enters your cells, and is translated into a protein, in this case, the coronavirus spike protein, which is then excreted from the cell. So in essence, your body makes this spike protein, and then your body makes antibodies to the spike protein, all because it's been instructed to do that. Your cells have been instructed to do that by this little piece of messenger RNA.

Thank you.

Related Centers and Programs: Vaccine Education Center

Last Reviewed on Nov 13, 2020