The type of vaccines used against COVID-19 do not interact with or alter human genetic code, also known as DNA, scientists say.
The unfounded claim spread on social media platforms in recent months as vaccines to prevent infections of the disease were being developed by pharmaceutical companies, including candidates from Pfizer/BioNTech, Moderna and Oxford/AstraZeneca.
Despite being repeatedly debunked and fact-checked as false, the claim has resurfaced this week after a Wisconsin hospital pharmacist accused of intentionally ruining a batch of doses of the Moderna vaccine told investigators he believed in the theory.
Steven Brandenburg, 46, was detained by police last week after allegedly removing 57 vials of the vaccine from a refrigerator and leaving them out for two nights, seemingly spoiling 570 doses because they have to be stored at a specific temperature.
The Ozaukee County District Attorney, Adam Gerol, said Brandenburg was an admitted conspiracy theorist who told police he believed the vaccine could change people's DNA, WDJT-TV reported. Brandenburg was fired from his job at Aurora Medical Center.
The unfounded claim about DNA changes is far from new, and has sporadically spread on Facebook as the disease caused by the novel coronavirus continued to surge across the county—a pandemic that has claimed more than 350,000 lives in the U.S.
A new and possibly more transmissible strain of the disease, named B.1.1.7, has since been recorded in multiple U.S. states, including Colorado, California and Florida.
The approved COVID vaccines—which are expected to either work or be adapted for the new variants—are based around Messenger RNA (mRNA), a molecule that essentially teaches humans cells how to trigger an immune response to the disease.
In traditional vaccines, a piece of a virus, known as an "antigen," would be injected into the body to force the immune system to make antibodies to fight off future infection. But mRNA-based methods do not use a live virus, and cannot give someone COVID.
Instead, mRNA vaccines give cells the instructions to make a "spike" protein also found on the surface of the virus that causes COVID. The body kickstarts its immune response by creating the antibodies needed to combat those specific virus proteins.
Once the spike protein is created, the cell breaks down the instructions provided by the mRNA molecule, leaving the human immune system prepared to combat infection. The mRNA vaccines are not a medicine—nor a cure—but a preventative measure.
Gavi, a vaccine alliance partnered with the World Health Organization (WHO), has said that mRNA instructions will become degraded in approximately 72 hours.
It says mRNA strands are "chemical intermediaries" between DNA in our chromosomes and the "cellular machinery that produces the proteins we need to function."
But crucially, while mRNA vaccines will give the human body the blueprints on how to assemble proteins, the alliance said in a fact-sheet last month that "mRNA isn't the same as DNA, and it can't combine with our DNA to change our genetic code."
It explained: "Some viruses like HIV can integrate their genetic material into the DNA of their hosts, but this isn't true of all viruses... mRNA vaccines don't carry these enzymes, so there is no risk of the genetic material they contain altering our DNA."
The Centers for Disease Control and Prevention (CDC) says on its website that mRNA vaccines that are rolling out don't "interact with our DNA in any way," and "mRNA never enters the nucleus of the cell, which is where our DNA (genetic material) is kept."
Mark Lynas, visiting fellow at Cornell University's Alliance for Science, told Reuters back in May last year that DNA-altering conspiracy theories were "often spread intentionally by anti-vaccination activists to deliberately generate confusion and mistrust."
"Genetic modification would involve the deliberate insertion of foreign DNA into the nucleus of a human cell, and vaccines simply don't do that," Lynas said.
The science was backed by Jeannette Dabanch Peña, infectious diseases professor of the University of Chile, who told AFP Fact Check last month that mRNA vaccines don't "manipulate" human DNA, as the conspiracy once again started to spread.
"They are only designed to express certain proteins so our body can identify them and produce the necessary defences. This is what a virus does naturally and it does not manipulate our genes," Peña continued, echoing the broad scientific consensus.