Blanton S. Tolbert, professor of chemistry at the College of Arts and Sciences, and his research group study the basic biochemistry of viruses, including SARS-CoV-2, the virus that causes COVID-19. Since he was in graduate school, he has worked on the biological molecule RNA, ribonucleic acid, which is the active component of the Moderna and Pfizer vaccines.
Here, he shares his insight on how the COVID-19 vaccines work.
What is the difference between DNA, RNA and protein?
In biology there is a concept that is known as the central dogma of molecular biology, which describes the general flow of genetic information from DNA to RNA to proteins. DNA and proteins are quite common to most of us. DNA, which is an acronym for deoxyribonucleic acid, contains the instructions on how most organisms are made. DNA is converted to RNA, and RNA is then translated into proteins. You might think of DNA as the molecular autobiography of an organism, and RNA is the Cliff Notes or abridged version of that autobiography. By this analogy, RNA is a smaller version of the autobiography, but it still contains the important instructions to make proteins. Once proteins are made, they can be used to assemble the parts of an organism.
How do the COVID-19 vaccines work?
The Moderna and Pfizer vaccines are known as mRNA vaccines because they contain the reduced instructions for making the COVID-19 spike protein. They only contain instructions for making just one tiny part of the SARS-CoV-2 virus. The vaccines do NOT contain the instructions for making the entire virus. The spike protein sits on the outside of the COVID-19 virus, and the virus uses the spike protein to enter into cells during a viral infection. The spike protein is also the molecule that produces the immune response.
The Moderna and Pfizer vaccines work by packaging the spike mRNA into a protective coat that acts like a vehicle to deliver the mRNA into cells. Once delivered, our very own cellular machinery converts the mRNA vaccine into spike protein. The spike protein made from the mRNA in the vaccine stimulates our immune system to make antibodies against the spike protein. Our bodies are able to produce a protective immune response to SARS-CoV-2 just by using the reduced instructions stored in the spike mRNA. The Moderna and Pfizer vaccines do NOT cause COVID-19 infection because they only contain the mRNA for the spike protein, not the entire virus.
The Johnson & Johnson vaccine uses DNA of the spike protein instead of RNA. But the result is the same as with the other two vaccines—spike protein is made, and the immune response it generates protects the vaccine recipient from getting COVID-19 infection.
How could the vaccines be developed so quickly?
It turns out that the mRNA vaccine technology is not new. It has been researched in academic labs for a few decades, and the prevalence of COVID-19 infection around the world allowed the vaccines to be rapidly studied and approved in order to stop viral infections.
Dr. Tolbert, will you get the vaccine once you are eligible to receive it?
Absolutely. I am eager to receive any of the vaccines as soon as I am eligible. I understand the science behind the vaccine and trust its safety. In my opinion, getting infected with the COVID-19 virus carries far greater health risks than getting one of the vaccines.