Moderna vials sit on a table in Bridgeport, Connecticut, on April 20, 2021 (AFP/Joseph Prezioso) (AFP / Joseph Prezioso)

Video falsely claims Moderna Covid-19 vaccine contains unsafe ingredient

  • This article is more than one year old.
  • Published on May 26, 2021 at 17:35
  • 4 min read
  • By AFP USA
An online video says the Moderna Covid-19 vaccine contains a cancer-causing ingredient that is not fit for human use. But the warning in the data sheet used to “prove” the claim is about chloroform, a toxic compound that regulators do not list as being in the vaccine.

“That’s weird. Not for human or veterinary use?” reads the text shared with a TikTok video that has been watched more than 1.3 million times since May 14, 2021.

The narrator in the video, which has also been shared on Instagram, searches for a breakdown of what is in Covid-19 vaccines, clicking on a chemical supplier’s website that provides details about a product called SM-102, the same name as one of the ingredients in Moderna’s vaccine.

Screenshot of videos taken on TikTok and Instagram on May 20, 2021

SM-102 is a lipid that helps to shield fragile mRNA molecules -- the messenger ribonucleic acid technology used in such shots -- and deliver them into cells.

The video features the first page of a Safety Data Sheet for SM-102, available on the website of Cayman Chemical, a biotech company based in Ann Arbor, Michigan, which clearly indicates that the substance is “for research use only.”

The person in the video uses health warnings featured in the document, such as “suspected of causing cancer” and “suspected of damaging fertility or the unborn child,” to suggest that SM-102 -- and thus the vaccine -- is dangerous.

The sheet does contains those warnings -- including about risks of cancer and infertility -- that are required by regulatory agencies:

Screenshot taken from on May 19, 2021

But the warnings stem from Cayman Chemical SM-102 mixture’s major component, chloroform -- a substance not listed as an ingredient in Moderna’s vaccine by American, European or Canadian regulators.

Cayman Chemical told AFP that following the spread of misinformation, it released a statement on May 19, which explains that SM-102 is among the products it makes for “research use only” and these “are intended only for in vitro or animal (exploratory or preclinical) use.”

“Chemicals under the same name can have differing designations such as grade or formulation that are defined by their manufacturing protocols and intended use,” the company said.

Screenshot taken from

The statement emphasized: “Neither the National Institute for Occupational Safety and Health (NIOSH), Registry of Toxic Effects of Chemical Substances (RTECS), or the European Chemicals Agency (ECHA) Classification and Labelling Inventory list any hazards associated with SM-102.”

Contacted by AFP about the safety claim, Moderna did not reply.

But Michigan State University researchers said there is no indication that the manufacturing process would incorporate any chloroform.

Dr Norbert Kaminski and Dr Jinpeng Li, members of the Center for Research on Ingredient Safety at Michigan State University, said in an emailed statement: “While one company may use chloroform in the production of an ingredient, it does not suggest that Moderna would use that product in the manufacturing of their vaccine.”

Dasantila Golemi-Kotra, a microbiologist at York University, said that companies are required by law “to list all the ingredients that are present to levels that may be risky to humans.”

She also explained that “the Safety Data Sheet very clearly indicates (for someone that knows and is willing to learn how to read such documentation) that SM-102 is a mixture of two chemicals: the active ingredient, the lipid, and a solvent, chloroform. SM-102 is not the pure lipid, but rather it constitutes 10 percent of the mixture SM-102.”

She pointed to a further section of the Safety Data Sheet indicating that while chloroform is listed under “dangerous components,” the SM-102 molecule is not:

Screenshot of a document from on May 19, 2021

Additional safety tables in the document also show that chloroform, not the SM-102 lipid, is the ingredient targeted by the various warnings:

Screenshot taken from on May 19, 2021

Raymond Tellier, a microbiologist at the McGill University Health Center, also confirmed that “a careful reading of the linked Material Safety Data Sheet (MSDS) clearly shows that all the warnings contained refer to chloroform.”

The claims about the safety of the Moderna shot are part of a flood of false or misleading assertions about vaccines and their safety that have spread online as the United States pushes ahead with its immunization campaign against Covid-19.

EDIT: The first paragraph of this article was updated on May 26, 2021.

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