No, Covid-19 Vaccines Won’t Change Your DNA

Credit: Andriy Onufriyenko / Getty Images

The false claim that coronavirus vaccines will alter a person’s genetic code has spread on social media platforms in recent months as companies like Pfizer and Moderna sprinted to develop vaccines against the highly contagious virus responsible for the Covid-19 pandemic.

The notion even led to a Wisconsin pharmacist to intentionally remove 57 vials of the Moderna Covid-19 vaccine from the fridge at the hospital where he was working and leave them out at room temperature, hoping they would spoil. The man admitted to police that he had deliberately tried to sabotage his hospital’s vaccination efforts because he believed the vaccine could harm people and “change their DNA.”

The confusion may arise from the fact that Pfizer and Moderna’s vaccines use a tiny piece of genetic material called messenger RNA to spur an immune response in the body. Though sometimes called “genetic vaccines,” they can’t modify a person’s DNA in any way.

“Messenger RNA vaccines do not have the capacity to change your DNA,” Shobha Swaminathan, MD, an associate professor of medicine at Rutgers University and medical director of infectious diseases practice at University Hospital in Newark, tells the Medium Coronavirus Blog. Swaminathan is also the principal investigator for Moderna’s phase 3 clinical trial at Rutgers.

You might remember from high school biology that DNA — the genetic material that makes up who we are — resides in the nucleus of the cell. DNA codes for proteins that your body needs to carry out various biological processes. To do that, DNA needs an intermediary: messenger RNA, or mRNA, which carries instructions for making proteins.

Your DNA initially makes mRNA in the nucleus. From there, the mRNA leaves through a one-way door. “It never goes back in,” explains David Verhoeven, PhD, assistant professor of veterinary microbiology and preventive medicine at Iowa State University, who develops vaccines for animal testing. Once the mRNA leaves through that door, the cell’s machinery starts making proteins.

The big difference between DNA and RNA is that DNA is your permanent genetic code; RNA is ephemeral. It sticks around in the body for a few days at most. “It’s just a temporary transcript between the DNA and the final protein that it makes,” says Verhoeven, whose lab is working on an mRNA vaccine for Covid-19.

What vaccine scientists have been able to do in the lab is engineer mRNA that tells the body to make a version of a key protein on the coronavirus called the spike protein. But the fleeting nature of mRNA means it won’t work well if it’s nakedly injected into the body. The mRNA would degrade too quickly before it can make enough of the spike protein to spur an immune response. So scientists have packaged the mRNA into fat bubbles called lipid nanoparticles, which ferry the mRNA into cells. These protective nanoparticles keep the mRNA stable enough so that it has enough time to get into cells and make the spike protein.

But remember — mRNA never reenters the cell’s nucleus, where your DNA resides. In other words, there’s no risk of it integrating with your DNA. “It stays outside the nucleus and tells the cells to produce those spike proteins,” Swaminathan says. “Once it does its job, the mRNA disintegrates in a very short period of time.”

When cells start making the spike protein, the immune system recognizes it as foreign and generates antibodies that kill those proteins. The immune system will then remember that foreign invader — in this case, the coronavirus spike protein — and mount a response if it ever encounters it again. This is the basic idea behind any vaccine.

Once the mRNA disintegrates, your cells stop making the spike protein. And that’s how mRNA vaccines work. While the idea of “genetic vaccines” may sound scary, there’s no reason to think that they’ll have a lasting effect on our genetic code.



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