Here’s why Pfizer, Moderna COVID vaccines do not affect DNA, experts say
- Oops!Something went wrong.Please try again later.
Federal regulators are blasting Florida Surgeon General Joseph Ladapo for pushing what they say are unfounded and misleading safety concerns about Pfizer and Moderna’s COVID-19 vaccines.
Ladapo, Florida’s controversial top health official, last week advised against getting Pfizer and Moderna’s mRNA vaccines over concerns the shots could possibly deliver DNA contaminants into human cells. He said the contaminants could potentially affect people’s DNA, including the genes of their future children, and also raised concerns about a possible cancer risk.
The U.S. Food and Drug Administration, which previously addressed Ladapo’s concerns in a December letter, reiterated that the vaccines are safe, effective and do not affect a person’s DNA. Drug maker Pfizer and vaccine experts have also dismissed his claims.
“The FDA stands firmly behind the safety, effectiveness and manufacturing quality of the approved and authorized COVID-19 vaccines ... With over a billion doses of the mRNA vaccines administered and following very careful review of all the available scientific evidence, the FDA has not identified safety concerns related to the sequence of, or amount of, residual DNA,” the FDA said Thursday in an emailed statement to the Miami Herald.
The federal agency also chided Ladapo for not putting into context residual DNA in COVID-19 vaccines, saying it’s “misleading” to not place it “within the context of the manufacturing process and the known benefits of the vaccine.”
Ladapo maintains the FDA has not been transparent with the vaccines.
“It is my hope that, in regards to COVID-19, the FDA will one day be fully transparent, take accountability, and seriously consider its regulatory responsibility to protect human health, including the integrity of the human genome,“ he said Tuesday in a statement to the Herald.
This latest clash between Ladapo and the FDA comes after the surgeon general in December sent a letter to the FDA and the U.S. Centers for Disease Control and Prevention, questioning whether the shots were assessed for DNA integration.
This is not the first time Ladopo has sparred with the FDA and CDC over COVID vaccines. In March, responding to a letter Ladopo sent them questioning the vaccines’ safety and effectiveness, the two agency heads strongly criticized him for fueling vaccine hesitancy.
And last year his peers at the University of Florida medical school, where he was hired by Gov. Ron DeSantis-appointed trustees as a tenured medical school professor, blasted his COVID study, saying he violated medical research ethics by cherry-picking data to support an anti-vaccine hypothesis.
Let’s break it all down:
Could Pfizer and Moderna’s COVID vaccines affect DNA?
Ladapo is questioning the safety of Pfizer and Moderna’s COVID vaccines and whether the mRNA vaccines could possibly affect a person’s DNA, and the genes of their future children, by introducing DNA contaminants into cells.
The FDA says this is “implausible” and that animal studies found “no evidence for genotoxicity from the vaccine.” The agency also cited global surveillance data on over one billion doses of the vaccines administered that showed “nothing to indicate harm to the genome, such as increased rates of cancer.” Drug manufacturer Pfizer, the CDC and other health experts also say the vaccines do not affect DNA.
COVID-19 vaccines “do not enter the nucleus of the cell where our DNA (genetic material) is located, so it cannot change or influence our genes,” the CDC website states.
Is there DNA in the COVID-19 vaccines?
In his letter to federal officials, Ladapo references an October preprint analysis that found billions of DNA fragments per dose in Pfizer and Moderna’s COVID-19 vaccines in Canada. Preprints are not peer-reviewed nor published in an academic journal, the gold standard in medical research.
He also references a 2007 DNA vaccine FDA guidance, which the federal agency says was developed for “DNA vaccines themselves, not for DNA as a contaminant in other vaccines and is not applicable to the mRNA COVID-19 vaccines.”
Ladapo’s letter brings back into the limelight the DNA contamination theory that anti-vaccine advocates have touted, and vaccine supporters have blasted.
“If the risks of DNA integration have not been assessed for mRNA COVID-19 vaccines, these vaccines are not appropriate for use in human beings,” Ladapo said last week in a statement.
While there is some residual DNA in the shots because of the way mRNA vaccines are made, the vaccines have met all safety and quality control standards, including internationally agreed upon recommendations on how much residual DNA can be present in biological products, including mRNA vaccines, according to the FDA and drug maker Pfizer. Some residual DNA can be found in influenza, measles and chickenpox vaccines, experts say.
“The surgeon general is taking scientific facts and completely omitting the relevant context in order to scare people,” said Dr. Amesh Adalja, senior scholar at Johns Hopkins Center for Health Security, which studies pandemics and other infectious disease outbreaks. “There may be some DNA contamination in the vaccines but he’s using that fact to scare people as if that poses a health risk. So even if there is a small amount of DNA contamination, it’s below the limit of safety and it doesn’t actually pose any risk to people.”
Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia, who serves on an FDA advisory committee for COVID vaccines, told Scientific American that “trace quantities” of DNA — billionths to trillionths of a gram per vaccine dose — “are utterly and completely harmless.”
“The minute you say the word DNA, people think, ‘Oh, my God, there’s DNA in this? Is that going to affect my DNA?’” Offit told Scientific American. “But you have better chance of becoming Spider-Man” than being harmed by DNA from the COVID vaccines.
The FDA is also doubling down on the vaccine’s safety.
“In general, while concerns have been raised previously as theoretical issues, the available scientific evidence regarding the mRNA vaccines strongly supports the conclusion that the vaccines are safe and effective and have a highly favorable profile of benefit to risk,” reads the FDA statement provided to the Herald. “Additionally, it is simply a fact that millions of lives have been saved because of the COVID-19 mRNA vaccines, which most Americans undergoing vaccination have received.”
It’s worth noting that while COVID-19 vaccines have been linked to cases of myocarditis and pericadrditis, types of heart inflammation, federal health officials say these incidents are rare and that the benefits of vaccination outweigh the risks.
COVID uptick
Ladapo’s recommendation to not get vaccinated comes as the U.S. is experiencing another COVID uptick after the holidays. COVID infections, hospitalizations and deaths have increased in recent weeks, as the JN.1 variant sweeps across the country. The variant, a descendant of omicron, is estimated to make up about 62% of infections in the U.S., according to the most recent CDC estimates.
Fewer people in the U.S., including in Florida, have gotten the newly updated COVID-19 vaccine, which was rolled out in September. As of Dec. 30, about 19% of adults and 8% of children in the U.S. have received the new shot, the CDC says.
READ NEXT: Fewer in Florida are getting new COVID shot. Why they’re refusing — and what it means
What about monkey virus?
Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, also told Ladapo in the Dec. 14 letter that the vaccines don’t have SV40 proteins, a DNA virus found in monkey kidneys that can potentially cause cancer in humans.
Pfizer told the Herald in an email that while specific “non-infectious” parts of SV40’s DNA sequence, known as an SV40 promoter, were used in the COVID-19 vaccine’s “starting materials,” the actual virus itself is not present in the vaccine.
Ladapo insists Pfizer is obscuring the truth and that its COVID vaccine SV40 promoter/enhancer DNA “is biologically active and is not present in Moderna’s vaccine.”
“As I’ve previously stated, the FDA published their own guidance in 2007 that outlines protocol for assessing DNA integration. The importance of assessing for DNA integration is heightened due to the COVID-19 mRNA vaccine’s lipid nanoparticle delivery system,” Ladapo said in statement to the Herald Tuesday.
The federal agency says its 2007 guidance is for DNA vaccines, not mRNA vaccines.
“I directly asked the FDA to address whether any DNA integration assessments have been conducted and this question remains unanswered,” Ladapo’s statement reads.
An SV40 promoter is not the same as the full SV40 virus, and has long been used in molecular biology to help stimulate genes, researcher Kevin McKernan told the Associated Press last year. McKernan, a former research director at MIT’s Human Genome Project who now runs Medicinal Genomics, was the lead researcher in a preprint study last year that was referenced in social media posts pushing false claims that the vaccines had a cancer-causing monkey virus DNA in them. McKernan dismissed the social media claims as “fear mongering.”
Experts also told the AP that the SV40 promoter, on its own, can’t cause cancer because the part of the promoter that’s potentially cancer-causing, known as the T-antigen, isn’t present in the vaccine.
How do Pfizer, Moderna’s mRNA COVID vaccines work?
While some vaccines put a weakened or inactivated germ in your body, Pfizer and Moderna’s mRNA COVID vaccines do not infect you with COVID. Instead, these vaccines teach your body to create antibodies against COVID.
How?
The vaccines instruct your body to create a harmless version of the spike protein that is on the outside of the COVID-19 virus onto your cells, triggering your immune response, according to the Mayo Clinic.
Ladapo questions whether the “lipid nanoparticles” used to help deliver the vaccine to your cells could also possibly deliver DNA contaminants and is recommending doctors “prioritize patient access to non-mRNA COVID-19 vaccines and treatment.”
Adalja told the Herald that not only did the vaccines undergo a rigorous process to get FDA approval, but the lipid nanoparticles are “a major scientific breakthrough.” The lipid nanoparticles are safe molecules used in other medications and they’re part of the vaccine delivery mechanism to help the shots work better, he said.
“Dr. Ladapo represents the voice of the Dark Ages,” said Adalja. “People should ignore him as if to ignore any kind of charlatan that’s selling snake oil.”
