Fact Check-Moderna’s chief medical officer did not say mRNA vaccines alter DNA

Social media users have been sharing articles that claim Moderna’s chief medical officer Tal Zaks has said mRNA vaccines – like the Moderna vaccine for COVID-19 – alter DNA. This claim is false. It is based on comments made by Zaks that have been misconstrued, and Reuters has found no evidence of him making any such comments elsewhere.

The posts (here ,  here ,  here) show either a link or a screenshot taken from an article that has been copied verbatim on multiple websites here  , here  and here . Every site leads with the same headline: “Bombshell: Moderna Chief Medical Officer Admits mRNA alters DNA.”

According to the article, evidence of the claim in the headline can be traced back to Zaks giving a TedTalk in 2017 (here). It specifically points to Zaks’ turns of phrase such as: “We are actually hacking the software of life” and: “We think about it as an operating system. So if you could actually change that… if you could introduce a line of code, or change a line of code, it turns out it has profound implications for everything.”

After quoting Zaks (here), the article then makes its own conclusion: “When ‘changing’ a line of code or ‘introducing’ a line of code (referring to DNA), the ‘code’ or DNA is then altered, meaning the individual or ‘subject’ has now had their genome changed to what the ‘scientists’ have coded. The individual or subject is no longer a creation of God but a creation of man, meaning the individual or subject could be the object of a ‘patent’.”

This is not true. It is a conclusion based off a misrepresentation of quotes made by Zaks, who at no point in his TedTalk says mRNA vaccines will change a person’s DNA. In fact, his explanation and diagram of an mRNA flu vaccination at work demonstrates the opposite.

“So here’s all the biology you need to know in 30 seconds,” says Zaks at the beginning of his explanation. “Our body is made out of organs, our organs are made out of cells, and in every cell there’s this thing called messenger RNA, or mRNA for short, that transmits the critical information from the DNA, our genes, to the protein, which is really the stuff we’re all made out of. This is the critical information that determines what a cell will actually do.”

While Zaks is speaking, he presents a diagram showing the cell. DNA is situated inside the nucleus, which sends mRNA out into the wider cell to a “protein-making unit” to instruct the unit to make a protein.

“So many of us get a vaccine,” Zaks continues as he begins to talk about the flu. “What is a vaccine? It is an injection in our arm where we get bits and pieces of the virus, the proteins, and that teaches our immune system to recognise the virus – so when we get infected we’re not sick.

“Now, imagine that instead of giving the protein, we would give the instructions on how to make the protein, how the body can make its own vaccine. That’s an mRNA vaccine.”

Zaks then returns to his diagram to show the mRNA entering the cell and travelling straight for the “protein-making unit” to instruct it to create a specific protein. It does not interact with the nucleus – and therefore not the DNA (here). Zaks adds: “So the traditional approach has proteins floating around your cells. An mRNA vaccine approach has the cells themselves in your own body making the vaccine.”

This is how Moderna’s mRNA vaccine for COVID-19 works (here  ,  here) , as well as the shot created by Pfizer/BioNTech (here ,  here). Both inject a small piece of genetic code from SARS-CoV-2, the virus that causes COVID-19 disease, to instruct human cells to create the virus’ unique spike protein. Its aim is for the immune system to recognise and eliminate the spike protein so it is trained to target this structure if it ever comes into contact with the real SARS-CoV-2. After this process, the mRNA is broken down, and does not stay in the body (here). The Moderna website explains the mRNA technology in more detail here .

The additional context to Zaks’ talk shows the Moderna boss was using terms such as “operating system” and “software of life” metaphorically. Reuters has also previously debunked claims related to the use of the former phrase on Moderna’s website (here), as well as other false claims that COVID-19 vaccines can change a person’s DNA here , here , here and here .


False. mRNA vaccines do not alter the recipients’ DNA and Moderna CMO Tal Zaks did not say they did.

This article was produced by the Reuters Fact Check team. Read more about our fact-checking work here .