CLAIM: Vaccines developed for COVID-19 contain a cancer-causing virus DNA found in monkeys.

AP’S ASSESSMENT: False. Public health officials and the lead researcher of a study cited in many of the social media posts say there’s no monkey virus DNA in the inoculations approved by government regulators. Some COVID-19 vaccines utilize DNA molecules derived from Simian Virus 40, but that’s not the same as the virus itself and the molecules aren’t cancer-causing.

THE FACTS: Social media users are claiming a dangerous ingredient has been discovered in coronavirus vaccines: cancer-causing “monkey virus” DNA.

“Green Monkey DNA confirmed present in COVID jabs,” read one tweet that was retweeted more than 2,500 times.

The post shared an article reporting on the claims with the headline: “Monkey Virus DNA Found in COVID-19 Shots.”

“Found: Cancer-Promoting Simian Virus 40 (SV40) in Pfizer Vials,” read another headline shared in a screenshot on Instagram.

But there’s no evidence to support the claim that the COVID-19 vaccines contain monkey DNA nor the virus known as SV40, according to public health officials and the lead researcher of a recent study cited in some of the social media posts.

Spokespersons for the Centers for Disease Control and Prevention and the U.S. Food and Drug Administration referred to their respective websites, where the ingredients of approved vaccinations — and the long running myths and concerns around them — are explained.

“There is no evidence to indicate the presence of SV40, a virus found in monkey kidneys that can potentially cause cancer in humans, in the formulation of COVID-19 vaccines,” wrote Alessandro Faia, a spokesperson for the European Medicines Agency, the Netherlands-based European Union agency that regulates pharmaceuticals, in an email.

Pharmaceutical giant Pfizer also confirmed in an emailed statement that no monkey DNA was used in creating its version of the COVID-19 inoculation.

“The vaccine is a completely synthetic vaccine,” the company wrote. “There were preclinical animal challenge studies utilizing rhesus macaques; however, no part of our vaccine or studies utilized green monkeys. The claim that the vaccine includes monkey DNA is inaccurate.”

Kevin McKernan, one of the authors of the study cited in some of the posts, dismissed the claims as “fear mongering” and “click bait.”

He says researchers involved in the study, which is a “pre-print” that has not been published in a peer-reviewed academic journal, discovered an “SV40 promoter” in the Pfizer vaccine.

But that’s not the same as finding the full SV40 virus in the shot, stressed McKernan, a former research director at MIT’s Human Genome Project who now runs Medicinal Genomics, a Massachusetts company that sells DNA testing kits and other laboratory materials to cannabis companies.

“Promoters” are DNA sequences that help stimulate gene expression and have been long used in molecular biology, McKernan and other experts explained. In the case of the SV40 promoter, it happens to be derived from the SV40 virus.

“It’s just the volume knob that drives high level expression of anything put under its control, which in this case is just an antibiotic resistance marker,” wrote Phillip Buckhaults, director of the Cancer Genetics Lab at the University of South Carolina who was not involved with the study, in an email.

“The fear about the SV40 sequences is total nonsense,” he wrote. “The vaccine is not going to cause cancer. There is no cancer causing gene in the vaccine.”

The false claims play on decades-old fears of SV40 and increased risk of developing cancer, adds Michael Imperiale, a molecular biologist at the University of Michigan Medical School who was also not involved in the research.

From 1955 to 1963, up to 30% of polio vaccines administered in the U.S. were found to have been contaminated with SV40, which came from monkey kidney cell cultures that had been used to make the vaccines, according to the CDC website.

But subsequent studies found “no causal association” between the SV40-contaminated polio vaccines and cancer development, the CDC writes.

What’s more, the SV40 promoter, on its own, can’t cause cancer, said Imperiale. The part of SV40 that’s potentially cancer-causing, known as the T-antigen, isn’t present in the vaccine.

(AP)