No, mRNA Vaccines Don't Cause Cancer

How a breakthrough discovery about vaccine benefits is being weaponized to spread fear

The Science vs. The Spin

Last month, researchers published an important study about how mRNA COVID-19 vaccines affect our immune system. The findings are fascinating and highlight a beneficial aspect of these vaccines that extends beyond their targeted protection against COVID-19.

Unfortunately, this research has been dramatically mischaracterized by certain groups, including an article from Children's Health Defense (CHD) claiming the study shows "mRNA vaccines are linked to genetic changes that can cause cancer and autoimmune disorders."

This is categorically false.

(A bit more backstory: The claims originated from a Substack post published last month by Alex Berenson, a former New York Times reporter who has become influential in vaccine discourse. According to Science Feedback, "Berenson became a notable source of health misinformation during the COVID-19 pandemic" despite "lacking the relevant qualifications (Berenson has no scientific or medical training)." His Substack has drawn more than 240,000 subscribers. Children's Health Defense later amplified the post in their publication The Defender.)

We reached out directly to the study's authors, who confirmed this interpretation is "complete nonsense." Let’s discuss…

What the Study Actually Found

The researchers discovered that mRNA COVID-19 vaccines not only generate antibodies (which we already knew), but also create what scientists call "epigenetic changes" in certain immune cells called macrophages.

In simple terms, the vaccines help train our innate immune system (the body’s first line of defense that fights off infections in a general way) to become better at responding to future threats, even ones unrelated to COVID-19. This phenomenon is called "trained innate immunity" and has been observed with other vaccines like BCG (for tuberculosis).

What Are Epigenetic Changes?

Let's break this down:

• The ‘genetic changes’ that the CHD article is referring to are in fact epigenetic changes. Epigenetic changes are NOT genetic mutations. They don't alter your DNA sequence. It is genetic mutations that contribute to cancer development and not epigenetic changes.

• You can think of epigenetic changes as adjustments to how your genetic instruction manual is read or expressed - like turning the volume up or down on certain genes - rather than changes to the instructions themselves. The specific modifications observed in the study help “bookmark” certain pages in our immune cells’ instruction manual, making them easier to access when needed for fighting infections.

• They happen constantly in our bodies in response to everyday influences - diet, exercise, stress, aging, and immune challenges such as infections.

• The specific change found (H3K27ac) is associated with "turning on" genes that help immune cells fight infections more effectively.

As the study author, Dr. Jan Rybniker, explained: "Epigenetic changes occur in human cells every day in response to environmental influences. By [CHD's] logic, one could just as easily claim that an influenza infection causes cancer."

For more on epigenetics and how they work, the National Human Genome Research Institute offers an excellent explanation.

The Cancer Claim: A Bridge Too Far

The CHD article makes an enormous leap by connecting these immune system changes to cancer. Here's why that's wrong:

1. Cancer requires genetic mutations - actual changes to DNA sequences - that the mRNA vaccines do not cause.

2. While cancer cells can have epigenetic changes, these occur alongside genetic mutations in cells that are already cancerous.

3. The specific epigenetic changes observed in the study primarily affected genes involved in immune function (70% according to gene analysis), not cancer pathways.

4. The affected cells (macrophages) have a short lifespan of about 3 days, making persistent problematic changes unlikely.

The cancer claims make a fundamental logical error. They note that certain epigenetic changes can be found in some cancers, then jump to the conclusion that finding similar changes after vaccination must mean vaccines cause cancer. This is like claiming that because firefighters are present at fires, firefighters must cause fires. Context matters tremendously when interpreting biological changes. The same type of cellular changes can have completely different effects depending on which cells they occur in and what triggered them. In fact, research published in Cell found that similar epigenetic changes in certain immune cells can actually help fight cancer (see below), highlighting just how context-dependent these processes are.

A Feature, Not a Bug

Far from finding concerning changes, the researchers discovered a mechanism that helps explain how vaccines can provide broader protection than just against their target disease - a phenomenon scientists call "trained innate immunity." This can actually be considered a beneficial "side effect" of mRNA vaccination. Trained innate immunity:

• Has previously been documented with other vaccines

• Helps the immune system respond better to a range of threats

• May explain why some vaccines provide broader protection than just against their target disease

The study actually suggests this mechanism could lead to improvements in future vaccine designs and might help us better understand how vaccines protect against unrelated infections. This represents an exciting advance in our understanding of how vaccines work, not a safety concern.

Why This Matters

Science communication is challenging. Complex findings can be misinterpreted innocently or deliberately twisted to promote existing narratives. As Dr. Rybniker noted in our correspondence, "It is complete nonsense to link these findings to cancer or any other disease."

When evaluating scientific claims, especially those that seem alarming:

1. Consider the source and their expertise.

2. Look for statements from the original researchers.

3. Check whether mainstream scientific organizations support the interpretation.

4. Remember that extraordinary claims require extraordinary evidence.

In a striking contrast to claims that mRNA vaccines cause cancer, researchers are actively exploring how this technology can help fight cancer. A 2023 study published in Nature showed promising results using personalized mRNA vaccines to treat pancreatic cancer, with half of the participants responding positively to the treatment. Similar approaches are being investigated for other difficult-to-treat cancers, highlighting how mRNA technology's ability to train the immune system represents a breakthrough with life-saving potential rather than a health risk. (Note: mRNA technology is also showing promise for infectious disease prevention against flu, HIV, Zika, Ebola, pertussis, tetanus, diphtheria, Lyme disease, and other diseases. The potential is truly incredible.)

A Note From the Researchers Who Led The Study

In our correspondence with the study's authors, they expressed concern about how their work was being misrepresented. They emphasized that epigenetic changes are normal, temporary regulatory processes that don't permanently alter DNA.

As scientists continue exploring how vaccines enhance our immune protection, let's appreciate the remarkable ways our bodies learn to defend us, and be wary of those who twist these discoveries to promote fear rather than understanding.

Stay Curious,

Unbiased Science

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