Do DNA Fragments in COVID-19 mRNA Vaccines Cause Harm?

Dr. Paul Offit explains why it’s virtually impossible for DNA fragments in COVID-19 mRNA vaccines to cause harms, such as cancers or autoimmune diseases.

Dr. Offit describes what would have to happen in order for DNA fragments to cause harm by explaining three protective mechanisms in our cells that DNA fragments from mRNA vaccines cannot overcome. First, the cytoplasm has immune mechanisms and enzymes that destroy foreign DNA. Second, the fragments would have to enter the nucleus, which requires a nuclear membrane access signal that these DNA fragments don't have. Third, even if they were able to enter the nucleus, the fragments would need to have an enzyme called integrase to become part of our DNA, which they also don’t have.

These facts should be reassuring to anyone concerned about a health risk caused by DNA fragments in vaccines.


Do DNA fragments in COVID-19 mRNA vaccines cause harm?

Paul Offit, MD:  In November 2023, a physician scientist testifying in front of Congress said that the mRNA vaccines made by Pfizer or Moderna contained fragments of DNA. He then took it one step further. He said that these DNA fragments could integrate into our DNA, causing cancers, like leukemia or lymphoma, or autoimmune diseases or other problems. This was in November of 2023.

Now, was he right? Is that true what he had said?

So, in order to understand the answer to that question, we need to go back to the beginning. How do you make mRNA vaccines? The way they're made is you have a starting material that consists of a DNA plasmid into which is cloned a DNA piece that represents the SARS-CoV-2 spike protein. Then there's a series of steps to amplify that SARS-CoV-2 spike protein DNA that is ultimately then converted to messenger RNA, purified and filtered, and then eventually treated with an enzyme that would cut any residual DNA and filtered and purified again.

So, is it possible that these DNA fragments from that starting material could end up in the final material? And the answer is yes, but in very small quantities. And by very small I mean nanograms, which is billionths of a gram. So, could that be harmful? Well, in order for it to be harmful, it would have to get into our DNA, which is virtually impossible, and here's why. First, these DNA fragments would have to enter the cytoplasm, which is that part of the cell outside of the nucleus, and our cytoplasm hates foreign DNA. It has innate immune mechanisms as well as enzymes to destroy foreign DNA. Then the DNA would have to enter our nucleus, which would mean it would have to cross the nuclear membrane, which requires a nuclear membrane access signal, which these DNA fragments don't have. Even if they were able to get into our nucleus, which they can't, they would have to then integrate into our DNA with an enzyme called integrase, which then cuts our DNA, and it would allow these DNA fragments to insert themselves into our DNA. But they don't have these kind of integrases. So, it's impossible; it's virtually impossible for these DNA fragments to do any harm. They are clinically and utterly harmless.

And, and this fear of foreign DNA is a little far-fetched. First of all, we are colonized with trillions of bacteria, including trillions of bacteria that line our intestinal tract, which is a vast amount of foreign DNA to which we're exposed. Also, assuming that we live on this planet and that you eat animals or plants on this planet, you are ingesting foreign DNA, some of which ends up in your circulation, especially plant DNA, at much larger quantities and in much larger fragment than we see with these small DNA fragments in vaccines.

So, I'm trying to reassure you that this isn't a problem. I think it's unfortunate that that physician scientist tried to make it sound like a problem because all he did was scare people unnecessarily.

I hope this helps. Thank you.