No sign that the COVID-19 vaccines’ spike protein is toxic or ‘cytotoxic’

The headline on a YouTube video and a person who speaks in it make a troubling claim about the way the COVID-19 vaccines work. 

"Spike protein is very dangerous, it's cytotoxic," they say, referring to the molecule that triggers the body’s immune system to produce antibodies against COVID-19 infection. 

It’s one of a number of widely shared social media posts alleging  that the vaccines are toxic or "cytotoxic," which means toxic to cells. 

The YouTube post, which was shared on Facebook, was flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.)

Experts say there is no evidence that the spike proteins produced by the Moderna and Pfizer vaccines, or the spike protein created by genetic material in the Johnson & Johnson vaccine, are toxic.

The 15-minute video, posted June 13, shows three people speaking on a podcast.

Bret Weinstein, who is identified in the video as an evolutionary biologist, is the one who says the spike protein in the vaccines "is very dangerous, it’s cytotoxic." 

Dr. Robert Malone, identified in the video as the inventor of mRNA vaccine technology, said he sent "manuscripts" months ago to the U.S. Food and Drug Administration claiming the spike protein posed a health risk. "And their determination was that they didn’t think that that was sufficient documentation of the risk that the spike was biologically active," he said.

The third person in the video is identified as "serial entrepreneur" Steve Kirsch, who said he is an engineer. He cited a claim by Canadian viral immunologist Byram Bridle that the vaccine doesn’t stay in the shoulder, where it’s injected, but "goes throughout your entire body, it goes to your brain to your heart." 

We rated False Bridle’s claim that the COVID-19 vaccines’ spike protein means people are being inoculated "with a toxin." 

Experts told PolitiFact there is no evidence to back his allegation that the spike protein produces a toxin that could cause serious health problems. 

COVID-19 vaccines work by triggering the human body’s natural immune response, without introducing a form of the COVID-19 virus itself. 

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The actual COVID-19 virus uses the spike protein to bind to cells, causing infection. But the mRNA vaccines, from Moderna and Pfizer-BioNTech, contain neither the virus nor the spike protein — just the genetic instructions for the body to make the spike protein associated with the coronavirus. 

Once the cell receives these instructions, it creates the protein and displays it on its surface. The immune system then spots the unknown protein and makes antibodies to protect against the virus. 

The Johnson & Johnson vaccine contains a modified adenovirus — not the COVID-19 virus — with a gene that induces cells to produce the spike protein, said vaccine expert Dr. Walter Orenstein at Emory University. As with the mRNA vaccines, this leads the immune system to recognize the spike protein as foreign and make an immune response against it, he said.

The federal Centers for Disease Control and Prevention, which calls the spike protein harmless, explains: "Our immune systems recognize that the protein doesn’t belong there and begin building an immune response and making antibodies, like what happens in natural infection against COVID-19. At the end of the process, our bodies have learned how to protect against future infection."

An FDA spokesperson told PolitiFact: "There is no scientific data to indicate that the spike protein in mRNA vaccines is toxic or that it lingers at any toxic level in the body after vaccination."

Responding to the claim made in the video, Emory’s Orenstein and vaccine expert Dr. Paul Offit of the Children’s Hospital of Philadelphia said they are not aware of any major dangers from the spike protein.  

"Where is the evidence?" said Offit. "No one is saying that vaccines are risk free. The minute there’s any reasonable signal that things are occurring in a vaccinated group and not in an unvaccinated group, then the FDA takes a closer look."

Offit noted as an example the federal response following reports of a small but higher-than-expected number of cases of heart inflammation — called myocarditis and pericarditis — developing in mostly young people after they received doses of mRNA-based COVID-19 vaccines.

The CDC announced June 10 that it will convene an emergency meeting on June 18 to discuss a possible link between the condition and the vaccines. 

The headline of a widely circulated YouTube post, and a person speaking in the video, say the COVID-19 vaccines’ spike protein "is very dangerous, it's cytotoxic."

U.S. public health authorities and vaccine experts say there is no evidence that the spike protein is toxic or cytotoxic.

We rate the post False.

CORRECTION, June 16, 5:02 p.m.: An earlier version of this fact-check incorrectly described how Johnson & Johnson's vaccine works. The rating is unchanged.