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Home » COVID vaccines and prion disease — zombie trope debunked

COVID vaccines and prion disease — zombie trope debunked

I’ve been around the block debunking various anti-vaccine claims for at least two decades, like the old “new” claim that COVID vaccines somehow cause prion disease. Yes, anti-vaxxers have made claims that vaccines caused prion disease in the past, and it was debunked then.

One thing I’ve noticed is that when an anti-vaxxer runs out of things to blame on vaccines, they’ll go back in time and find some old claim and revive it like a zombie. They do this with vaccines and autism (no link), vaccines and diabetes (no link), and so much else. Steve Kirsch (the anti-vaccine tech bro) loves bringing back zombie tropes about vaccines, often dislocating his shoulder while patting himself on the back for regurgitating these false claims.

Nevertheless, prion disease sounds scary, and it is. But does it have anything to do with COVID vaccines? As you can expect, it does not.

Let’s look at prion disease and examine any evidence that COVID vaccines increase your risk of the disease.

What is prion disease?

Before we get into the weeds, let’s first understand what a prion is. Prions are simply misfolded proteins that cause the misfolding of similar proteins in the body. Usually, prions come from an external source although they may spontaneously arise in an organism. The misfolded protein leads to various conditions, usually involving the brain or nervous system.

Prion diseases can affect both humans and animals and are sometimes spread to humans by infected meat products. 

Although there could be a lot of debate over this topic, prions are not living organisms. They are just a protein.

Several conditions are categorized as prion diseases:

  • Creutzfeldt-Jakob disease (CJD). A person can inherit this condition, in which case it’s called familial CJD. Sporadic CJD, on the other hand, develops suddenly without any known risk factors. Most cases of CJD are sporadic and tend to strike people around age 60. Acquired CJD is caused by exposure to infected tissue during a medical procedure, such as a cornea transplant. Symptoms of CJD quickly lead to severe disability and death. In most cases, death occurs within a year. 
  • Variant CJDThis is an infectious type of CJD that is related to “mad cow disease.” Eating diseased meat may cause the disease in humans. The meat may cause normal human prion protein to develop abnormally. This type of CJD usually affects younger people.
  • Variably protease-sensitive prionopathy (VPSPr). This is also extremely rare, it is similar to CJD but the protein is less sensitive to digestion. It is more likely to strike people around age 70 who have a family history of dementia. 
  • Gerstmann-Sträussler-Scheinker disease (GSS). Extremely rare, but occurs at an earlier age, typically around age 40.
  • KuruThis disease is seen in New Guinea. It’s caused by eating human brain tissue contaminated with infectious prions. Because of increased awareness about the disease and how it is transmitted, kuru is now rare.
  • Fatal insomnia (FI). This is a rare hereditary disorder that causes difficulty sleeping. There is also a sporadic form of the disease that is not inherited.

Prion diseases arise when the normal major prion protein (PrP), which is found on the surface of many cells, becomes abnormal because the abnormal prion causes a change in the 3D structure of the normal protein. Once this happens, the proteins clump in the brain, which leads to brain damage. This abnormal clumping can lead to memory impairment, personality changes, and movement difficulties. However, we don’t know much about these diseases because they are so rare and prions are so poorly understood.

All known prion diseases in mammals affect the structure of the brain or other neural tissue; all are progressive, have no known effective treatment, and are always fatal. Prions are extremely robust and cannot be destroyed by heat or most chemicals — that’s why cooking your prion-infected meat will not destroy the prion, and it can subsequently infect you.

I want to reiterate — prion diseases are very rare and are almost always fatal.

COVID vaccines and prion disease — any evidence?

The origin of the vaccines and prion disease myth started decades before the advent of COVID vaccines. This probably predates many of my readers, but back in the late 80s and early 90s, there was a panic about cattle in the UK carrying a form of variant Creutzfeldt-Jakob disease, bovine spongiform encephalopathy (BSE), often called mad cow disease.

Fetal bovine serum, which is derived from a bovine fetus, is used in many cell cultures because it contains growth factors that stimulate cell growth. Of course, it is used in cell cultures that are used to grow viruses for vaccines, including ones produced in the UK during this BSE outbreak. Connecting the dots, people were worried that the prions responsible for BSE could end up in our vaccines.

The UK’s Medicine Controls Agency (the British version of the FDA) was asked to “identify relevant manufacturers and obtain information about the bovine material contained in children’s vaccines, the stocks of these vaccines and how long it would take to switch to other products.”

However, no evidence even suggested that vaccines increased the incidence of mad cow disease. Scientists have looked into this matter further and concluded that:

Although the risk of transmission of vCJD to humans from such vaccines was considered theoretic and remote, the recommendation was made that vaccines use bovine materials originating from countries without endogenous MCD (mad cow disease). Mathematical models suggest that the agent of MCD first entered cattle feed in the United Kingdom around 1980; since the vast majority of initial cases of vCJD were born well before then, childhood vaccines were not likely to be the cause.

Furthermore, in an abundance of caution and to maintain the trust of the public in vaccines, the FDA has taken the precautionary step of eliminating the use of these materials from countries where BSE is endemic in the production of vaccines.

And let me make one more point — fetal bovine serum, or its components, is not used to manufacture any vaccine. It is used to grow the cells that allow for the production of the viruses, and the fetal bovine serum is eliminated before the vaccine is manufactured. Moreover, I do not believe that fetal bovine serum is used in the production of the mRNA molecules that end up in the COVID vaccines.

However, the anti-vaxxers have decided to invent a new way that prion diseases come from COVID vaccines. The loquacious Orac describes all of the dot-connecting between the vaccines and prion disease, and it takes some mental gymnastics to get there, but Orac tries to show how the dots are connected, at least in the mind of your average anti-vaxxer.

Essentially, the anti-vaccine community misuses a published paper, that proposes a hypothesis on how mRNA errors may lead to a misfolded protein through a process called frameshifting, where the translation of the mRNA to protein is shifted enough to cause an error in the protein. It did not provide experimental data that supported it, it was a scientist musing on a potential mechanism.

And let’s be clear, that paper had nothing to do with mRNA in COVID vaccines, which only code for the spike protein on the SARS-CoV-2 virus that causes COVID-19. The anti-vaccine community was trying to make something there when there was nothing there.

As I often discuss, the value of science-based medicine is that it relies upon biological plausibility, that is, does a medical claim have a plausible biological mechanism or not? Prions form when there is an error that causes the PrP protein to misfold which then leads to one of the prion diseases. The mRNA in the COVID vaccines DO NOT HAVE ANYTHING TO DO WITH PrP PROTEIN.

I’ve racked my brain and read more science about prions over the past couple of days than I have in my whole life (and I lived in the UK during part of the mad cow disease scare) — I cannot come up with any biologically plausible mechanism that would lead to any prion diseases from the COVD vaccines. None.

There is one laughable article, written by the notorious anti-vaxxer who has absolutely zero education or experience in any field of vaccinology, Stephanie Seneff, and published in a low-ranked journal, that tries to argue, without actual experimental data, that the mRNA vaccines could cause prion disease. She uses a specious, which shows her lack of education in many of the sciences that underlie vaccines, argument that the spike protein contains patches of amino acid sequences that are similar to prions.

However, anyone with any knowledge of protein chemistry knows that there are small bits of amino acid sequences that are similar between many proteins. But it’s not a sequence of 10 amino acids, out of hundreds that make up a protein, that matter. It’s the whole chain of amino acids that matters. It’s an amateur argument that doesn’t hold up to real science.

Summary of COVID vaccines and prion diseases

I know that prion diseases are scary — I did worry about it a lot when I lived in the UK. But it’s very rare. And it is not something that we should dismiss with a wave of the hand.

However, there is just no evidence that supports any link between COVID vaccines and prion disease. We have seen no uptick in prion diseases across the world, despite the mass vaccination efforts. We have no evidence that the mRNA in COVID vaccines has any effect on the PrP protein. We have nothing.

As I have stated, the COVID vaccines are safe. I hope I have stopped the zombies.


Michael Simpson

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