How Do DNA Vaccines Work?

Dr. Paul Offit explains how DNA vaccine technology works, using COVID-19 vaccine as an example.


How do DNA vaccines work?

Paul Offit, MD: Hi, my name is Paul Offit. I'm talking to you today from the Vaccine Education Center here at the Children's Hospital of Philadelphia. One of the strategies that’s used to make this SARS-CoV-2 vaccine, the COVID-19 vaccine, is called DNA vaccines. So, DNA is the blueprint of life; it's the genes that determines how our cells reproduce themselves. And so the way this strategy works is you take a small gene from the virus, the gene that codes for this so-called SARS-CoV-2 spike protein. So the spike protein is the protein that if you've seen pictures of this virus sort of emanates from the surface of the virus, it gives it its crown-like appearance, hence corona, and it's the protein responsible for attaching the virus to cells. If you can make antibodies to that protein that attaches the virus to cells then presumably you can prevent the virus from attaching to cells, or said another way, you can prevent the virus from infecting you. So, the way the DNA vaccine works is now this is just a small gene that codes for that spike protein. You inoculate it into people, that gene then enters the nucleus where it's then initially transcribed to messenger RNA, which then is translated to a protein, and that protein is the SARS-CoV-2 spike protein, which is then excreted from the cell, and then you make antibodies to that protein. So in other words, you make … your body makes the SARS-CoV-2 spike protein, and then your body makes antibodies to that protein.

This is not a strategy that's been used before, similar to the mRNA vaccines, it is not a strategy that also that’s been used before. But there's every reason to believe that both of these strategies can be useful, but we'll find out. And that's why we do these large, prospective, placebo-controlled phase 3 trials to prove that these vaccines work and prove that they're safe before we inoculate them into millions or tens of millions or hundreds of millions of people.

Thank you.

Related Centers and Programs: Vaccine Education Center

Last Reviewed on Dec 02, 2020