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Vivian Lam
By Vivian Lam November 23, 2021

DNA damage from COVID-19 spike proteins in lab study does not apply directly to COVID-19 vaccines

If Your Time is short

  • Findings from a lab-based study claiming that the spike protein of the COVID-19 virus causes DNA damage have been used to raise concerns about COVID-19 vaccine safety.

  • COVID-19 vaccines use a modified version of the spike protein that functions differently from what is programmed by the COVID-19 virus's genetic material.

  • Results need to be replicated in live animal or human studies to confirm clinical and physiological relevance.

The distinctive spike protein that covers the surface of the COVID-19 virus has inspired numerous misinformed claims about the vaccines that aim to prevent its spread. We have previously fact-checked claims on the purported toxicity of the spike protein relating to COVID-19 vaccines.

An Oct. 13 paper claiming that the spike protein can cause DNA damage has circulated on social media, causing uncertainty about whether these findings are relevant to the COVID-19 vaccines. Without more context, the title of a YouTube video — "Spike protein goes to nucleus and impairs DNA repair" — may sound alarming.

The lab-based context in which the study was conducted, however, limits its relevance to real life conditions outside the lab. And the study’s findings should not be directly translated to the COVID-19 vaccines, which use modified versions of the spike protein.

A blog post about the claim 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.) 

The study in question

Researchers from two Swedish universities introduced into isolated human kidney cells genetic material containing instructions to produce different proteins that make up the COVID-19 virus, including the spike protein. They then examined where these proteins are primarily located in the cell, and tested whether the proteins affected the cell's DNA damage repair system.

The researchers found that spike proteins were present in the cell nucleus, the part of the cell that houses DNA. They attributed a reduction in DNA repair efficiency to hindered recruitment of specific proteins involved in the repair process.

Their findings differ from previous studies that have found the spike protein to be located primarily outside the nucleus. Studies on the related coronavirus that causes SARS have also found its spike protein to be located in areas outside the nucleus. 

Relevance to vaccines

There are three main types of COVID-19 vaccines that are currently available or being tested in the U.S. Each one involves introducing modified versions of the spike protein to the body in order to prime the immune system to recognize the COVID-19 virus and build defenses against it. This modified version of the spike protein prevents it from assuming the structure that would normally allow it to fuse with the membranes of other cells, unlike the spike protein coded for in the kidney cell study.

Unanswered questions also remain.

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"There are a lot of caveats before we can say there is a direct correlation between the vaccines and DNA repair," said Andre Hudson, head of the Thomas H. Gosnell School of Life Sciences of the Rochester Institute of Technology.

One question, for example, is how the genetic material introduced into the kidney cells directed spike protein production: Was it the presence of the spike protein itself, or was it an overabundance of protein that led to their findings? 

Another question is replication: Can these findings be reproduced in other cell types or viruses that also use spike proteins? Does the age of the cells matter? "A lot of experimental details are still needed before you can make a definitive conclusion," Hudson said.

The Swedish researchers conducted an in vitro study, meaning it was conducted in a test tube or petri dish in a controlled lab environment. In vitro studies do not necessarily translate directly to what would happen in the much more complex biological environment of the body. 

Unlike the narrower parameters of an in vitro study, there are multiple cell types, immune responses and DNA repair mechanisms at play in people. "Though they may have evidence that it happened in a cell line in an in vitro system, that doesn't mean that's the way it would act or behave in animals or people," said Hudson. "Many studies have been done in vitro that don't translate to animal model systems."

Without replication in a study conducted on live animals or people, this study has limited clinical relevance to the COVID-19 vaccines.

Our ruling

Blog posts claim that a recent paper shows evidence that the spike protein on the COVID-19 virus can cause DNA damage, raising concerns about COVID-19 vaccine safety.

The study, however, contradicts findings from previous studies that were also conducted on isolated cells in a lab environment. Until their results are replicated in human studies, this has limited bearing on COVID-19 vaccines.

We rate the claim Half True.

Our Sources

Viruses, SARS–CoV–2 Spike Impairs DNA Damage Repair and Inhibits V(D)J Recombination In Vitro, Oct. 13, 2021

Mobeen Syed, Spike Protein Goes to Nucleus and Impairs DNA Repair (In-Vitro Study), Nov. 4, 2021

Signal Transduction and Targeted Therapy, A systemic and molecular study of subcellular localization of SARS-CoV-2 proteins, Nov. 17, 2020

Journal of Biological Chemistry, The SARS-CoV-2 envelope and membrane proteins modulate maturation and retention of the spike protein, allowing assembly of virus-like particles, Sep. 25, 2020

Nature Public Health Emergency Collection, Subcellular Localization of SARS-CoV Structural Proteins, 2006

Mayo Clinic, Different types of COVID-19 vaccines: How they work, Nov. 5, 2021

npj Vaccines, Distinguishing features of current COVID-19 vaccines: knowns and unknowns of antigen presentation and modes of action, Aug. 16, 2021

Videoconference interview, Andre Hudson professor and head of the Thomas H. Gosnell School of Life Sciences at the Rochester Institute of Technology, Nov. 19, 2021

MedicalNewsToday, What is the difference between in vivo and in vitro?, Aug. 31, 2020


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DNA damage from COVID-19 spike proteins in lab study does not apply directly to COVID-19 vaccines

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