Repeatedly debunked idea of “shedding” COVID-19 vaccines is still false

In the spring, claims began spreading widely that vaccinated people can "shed" the COVID-19 vaccine and harm those around them. Now, six months later, those false claims have come full circle.

A viral Oct. 27 blog post reads, "Pfizer Confirms COVID-Vaccinated People Can ‘Shed’ Spike Proteins And Harm The Unvaccinated." The claim can be traced to an April press release, when the hoax about vaccine shedding was proliferating.

The post 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.)

People vaccinated against COVID-19 cannot shed spike proteins to harm anyone. Many experts have debunked this notion, saying it is a conspiracy intended to undermine the vaccines. Experts also have said that the spike proteins produced through vaccination cannot infect others. 

The blog post says its source is a June 26 article from National Times Australia. That article, in turn, cites a May 4 post on Christians For Truth, which then references the ultimate source of the false information: an April 26 press release from America’s Frontline Doctors. That group has spread misinformation and conspiracy theories about the coronavirus.

In April, when America’s Frontline Doctors issued the press release, claims about vaccine shedding had emerged as a prevailing narrative in the anti-vaccine community, PolitiFact reported.

The Centers for Disease Control and Prevention says that vaccine shedding "can only occur when a vaccine contains a weakened version of the virus," and none of the COVID-19 vaccines in use in the United States meet that description. Other vaccines, such as measles and flu, use a piece or weakened version of the germ that is being vaccinated against.

The spike proteins referenced in the claim occur in the Pfizer and Moderna vaccines, which use mRNA technology. The CDC explains that mRNA vaccines work like this: The vaccine sends instructions to the body’s cells to make a piece of spike protein, which is also found on the surface of the virus that causes COVID-19. The cells make and display the protein, and "our immune system then recognizes that it does not belong there and responds to get rid of it." The resulting immune response produces antibodies.

The spike proteins are harmless, do not cause illness and do not last long in the body.

The claim also says that "Pfizer confirmed" that people can shed spike proteins, which is unsubstantiated. This part of the claim appears to have originated with an April 29 tweet from Dr. Simone Gold, the founder of America’s Frontline Doctors who also was arrested for actions stemming from her participation in the Jan. 6 riot at the U.S. Capitol.

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Gold’s tweet says "Pfizer trials warned men to stay away from pregnant women," referencing part of Pfizer’s trial protocol that explains when an "environmental vaccine exposure" during pregnancy is considered to have taken place. PolitiFact reported that the passage in the protocol "is described by experts as standard language meant to widely cover any possible exposures. …(E)xposure to a person who has received the Pfizer vaccine will not transmit virus particles."

A blog post claims, "Pfizer Confirms COVID-Vaccinated People Can ‘Shed’ Spike Proteins And Harm The Unvaccinated."

People vaccinated against COVID-19 cannot shed spike proteins, and spike proteins produced through vaccination cannot infect others. Vaccine shedding is not possible with the COVID-19 vaccines used in the U.S.

Pfizer did not confirm that people can shed spike proteins. That claim is based on a misinterpretation of the company’s clinical trial protocol.

We rate this claim False.