Study does not show that the Pfizer Covid-19 vaccine causes cancer

A video on Instagram claims that a study has “verified” that the Pfizer Covid-19 vaccine, which was marketed under the trade name Comirnaty, causes cancer.

The video shows screenshots of a study juxtaposed with images of frequent subjects of misinformation like Bill Gates, who we have written about many times.

A voiceover claims that the study found higher than permitted levels of “DNA contamination” in the Comirnaty vaccine when it was tested using a different method than the one used by Pfizer, who the speaker claims “didn’t test it properly”. The speaker goes on to say that the “DNA contamination’’ in the vaccine can easily get into [human] cells which can result in “uncontrolled growth or cancer”. 

However, the study referenced in the video does not look at whether the Comirnaty vaccine causes cancer. 

Furthermore, some experts have raised questions about the methods used in the study, and there is no evidence that Comirnaty is unsafe due to DNA contamination. 

We have previously fact checked false claims that Covid vaccines were not properly tested.

Misleading information risks causing alarm to the public and it may affect decisions people make about their own health.

We have written to the authors of the study and will update this article if a response is received.

What does ‘DNA contamination’ mean?

The “DNA contamination” the video mentions appears to refer to small amounts of DNA being present in the final (vaccine) product. 

This is not unique to Comirnaty and small amounts of DNA fragments can be found in other biological medications and vaccines that have been used safely for many years. This is because these medications are partly produced in biological cells. 

The European Medicines Authority (EMA), which is responsible for evaluating and monitoring medicine safety across Europe, explains how plasmid (bacterial) DNA is used in the manufacturing of mRNA Covid vaccines, like Comirnaty, and that the manufacturing process contains steps to remove this once it is no longer needed.

However, despite these steps, biological products like vaccines can still contain some DNA fragments within the final product and the EMA says it has “seen no evidence linking the residual DNA to side effects”. There are international limits on the permissible amounts of DNA fragments to ensure that the amount of DNA left over in medicines remains below particular levels.

The Food and Drug Administration (FDA) provides specific guidance for industry testing standards at various stages of production in the US.

What is insertional mutagenesis?

The video claims that “DNA contamination” could cause something called “insertional mutagenesis” because Comirnaty “easily gets into human cells”.

The process of foreign DNA combining with host DNA resulting in a mutation (a potential concern raised in the study) is known as insertional mutagenesis. It can occur spontaneously or be induced deliberately. 

Scientists have been studying mutagenesis for many years and have applied these techniques to improve plant and animal genetics as well as for other organisms. 

Insertional mutagenesis has also been used as a tool to help identify the genes involved in the development of some cancers. 

What the video says about the vaccine and insertional mutagenesis is not entirely accurate because the vaccine product does not come into direct contact with our DNA once injected as it remains in the cytoplasm—the fluid outside the cell’s nucleus. 

Experts have argued that even if the vaccine product could come into contact with our genetic material in the cell nucleus, this is not likely to cause any harm for a variety of reasons. 

In a recent letter addressing similar concerns raised by a US public official, the FDA explained the implausibility of DNA fragments in mRNA vaccines combining with the host genome and also described the lack of evidence for this in animal studies.

The FDA also pointed out that ongoing worldwide surveillance following billions of doses of mRNA vaccines has not shown evidence of increased rates of cancers or other harm to the genome.

Similar claims have been reviewed by Full Fact and other fact checkers.

What did the study actually find?

The study referenced in the video used a technique called fluorescence spectroscopy as a method of detecting DNA fragment levels in both in date and expired batches of the Comirnaty vaccine. The authors reported that they found higher than permitted levels of DNA fragments.

Fluorescence spectroscopy is a scientific technique that gives information about the electronic structure of substances and is used in industries such as food, dairy and medicine.

The authors of the study suggest that this method is better than the other method (qPCR) used to quantify DNA concentration by Pfizer and other control laboratories.

Commenting on the reliability of the study via the Science Media Centre, a postdoctoral scientist told Full Fact that “an ideal approach to quantify DNA would be to use multiple complementary approaches” and this is because both methods of DNA quantification have their own inherent limitations. 

They also went on to point out that whilst it is worthwhile to debate different methods of analysing mRNA vaccines, it is not surprising that a different analytical method led to different results. They also note that the study did not directly compare the different methods.

Most importantly, the expert agreed that the study did not provide evidence for or conclude that Comirnaty causes cancer.

What about vaccine monitoring?

In the UK, the Medicines and Healthcare products Regulatory Agency (MHRA) is responsible for monitoring the safety of medicines and healthcare products.

The MHRA’s Yellow Card scheme provides continuous safety monitoring and enables healthcare professionals and the public to report any medication related concerns.

We have written previously about vaccine misinformation.