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Gene-Therapied Pork or the Fear of RNA Vaccines in Livestock

Some pigs are immunized using RNA vaccines, which anti-vaxxers are claiming are not tested for safety and could harm us. This is not true.

“How long have you been consuming gene therapied pork?” That’s the question Joe Mercola, snake oil salesman supreme and one of the world’s richest doctors, recently asked on his website. (His article has now been moved to his paid Substack blog). The use of RNA-based vaccines, like the ones that were deployed against COVID-19, is not limited to humans; Mercola just found out they are used in livestock as well, and he worries about the technology damaging the food we eat and, ultimately, harming us.

Should you be worried about pork messing with your DNA? If we are to believe Mercola, the RNA vaccines aimed at pigs are not tested for safety, turning meat consumers into, well, guinea pigs. The reality is that potential risks have been mitigated both in the design of these vaccines and by multiple layers of safety testing, but none of these important details will get in the way of anti-vaxxers betting the farm on framing new vaccine technologies as hubristic genetic engineering.

How RNA vaccines work

In a way, vaccines over time have become less coarse and much more precise. We used to deliver to the body the entire microbe, either dead or severely impaired, as a means of triggering immunity without infection. Then, we became able to isolate a part of the microbe that our immune system could identify. Now, we have the nimbleness to deliver the recipe that codes for the part of the microbe our immune system needs to see, and that recipe comes in the form of a messenger RNA (mRNA) molecule.

This increased precision, though, comes at a cost. Whereas older vaccine technologies were readily understood by the public—you take the flu virus, kill it, and inject it into the body like a harmless “wanted” poster—newer ones are harder to grasp. They may be perceived as less natural, and the fear of uncontrolled genetic manipulations can rear its head and be fed by anti-vaccine influencers.

That fear can be alleviated in part by simply understanding how a mRNA vaccine works. Let’s take Merck Animal Health’s swine flu vaccine for use in pigs. It contains a piece of RNA that codes for part of the swine flu virus. That RNA is transported inside of a disabled virus, which acts like a capsule. This combination of RNA inside of this viral capsule is called the RNA Particle and it is injected into the pig. These particles are taken up by specific cells of the pig’s immune system known as dendritic cells. The dendritic cells translate the swine flu RNA into a swine flu protein, which they then display at their surface like little flags. These flags are used by other cells of the immune system to prime them and create a memory of the encounter. If these cells ever see the actual swine flu virus, they will react quickly and efficiently. (For a short animation of this process, I highly recommend this video from the Children’s Hospital of Philadelphia on the COVID-19 mRNA vaccines.)

All this talk of genetic material and inactivated viral capsules can make people anxious about what these things can do to the pig and, eventually, to the person eating the pig. Are there off-target effects? Can the flu RNA integrate itself inside of the pig’s own DNA and mess with its genome? Anti-vaccine activists would have you believe that no safety testing has been conducted to answer these questions. This is simply not true.

The reality of safety testing

In July of 2018, the Canadian Food Inspection Agency released a long document on Merck’s RNA Particle vaccine technology. They called it an “environmental assessment” and it was put together to help them make a decision. Canadian veterinarians wanted the ability to import this new swine flu vaccine from the US to Canada in cases where other flu vaccines were either unavailable or didn’t seem to work. The Food Inspection Agency had to decide if this new RNA vaccine was safe enough for animals, humans, and the environment. They looked at this question from several angles.

Can the disabled virus carrying the RNA—in this case a Venezuelan equine encephalomyelitis virus carrying a bit of swine flu RNA—make copies of itself inside the pig and cause disease? In theory, it can’t. For a virus to replicate, it needs to have its genetic blueprint intact, but the scientists here removed important genes that code for the scaffolding of the virus. It’s like opening a jigsaw puzzle box and finding half of the pieces missing.

In practice, studies were done where pigs were given very large doses of this vaccine, and swabs of both the nose and rectum as well as blood samples were taken up to two weeks later. If the empty shell of a virus carrying the vaccine instructions could make copies of itself, these would be detectable in the samples, but they simply were not there. But it doesn’t end here. Every batch of vaccine is similarly tested: a sample of it is taken and dropped onto cells in the laboratory to see if it will infect them and make copies of itself. In short, the virus can’t theoretically replicate; it doesn’t replicate in test animals; and every batch of the vaccine is tested just in case.

Could the RNA inside the vaccine become DNA and integrate itself inside the pig’s genome, creating havoc? The problem is that the pig’s DNA exists inside the nucleus of the cell, and the vaccine RNA does not enter the nucleus. A similar concern of genome integration was voiced when the COVID-19 vaccines were rolled out, with some pointing at published evidence that it could happen, but the conditions in which it was shown to happen were highly artificial and swiftly criticized. As an expert scientist told me at the time, the probability of the COVID-19 coronavirus integrating into our genome, either through infection or through a vaccine that contained instructions for the spike protein, was “that close to zero that it doesn’t worry me.”

Will the swine flu vaccine particles be shed by the pigs and end up in other pigs and perhaps in the environment? The Food Inspection Agency found no evidence of that in the nasal secretions and faeces of pigs up to 14 days post-vaccine, nor in the faeces of laboratory mice up to 42 days post-vaccine. Also, these vaccine particles, only 106 to 108 of which are injected in each vaccine dose, are not exactly bulletproof. They are not stable at room temperature outside of the animal, and these types of viral shells are sensitive to loss of moisture, sunlight, acidic pHs, and run-of-the-mill disinfectants. Inside the vaccinated animal, the vaccine particles are taken up by dendritic cells, which migrate to lymph nodes and die within five days. Two weeks after vaccination, scientists cannot find these particles in a wide array of tissue samples from the animal. They simply do not persist in the body.

The Agency also looked at the vaccine’s safety in humans, even though it is meant for pigs. An attenuated and an inactivated vaccine against this Venezuelan equine encephalomyelitis virus were developed in the 1960s and 1970s and they were given to hundreds of humans who were involved in research on this virus. Moreover, 152 healthy human volunteers also received experimental vaccines based on the viral capsule used in the RNA swine flu vaccine in the context of recent clinical trials. No safety concerns were flagged then. And while it is true that swine flu can hop into a human host and cause disease—one such strain combined with a different influenza strain to give us the 2009 swine flu pandemic—the swine flu vaccine in question only contains the instructions for one piece of the flu virus. It is simply not infectious on its own.

Similar RNA Particles using the equine encephalomyelitis virus have been tested in many animal species, including rabbits, cattle, and macaques, showing no safety concern. On top of this, most livestock raised in Canada lives in biosecure facilities. They do not readily comingle with other animal species, thus further lowering any risk. As the environmental analysis concludes, rather mundanely, “Should the vaccine be spilled, it can easily be inactivated by commonly available cleaning and disinfection agents.”

The United States Department of Agriculture (USDA) website also contains information on the safety testing of many RNA Particle vaccines that were submitted for license approval, including a porcine epidemic diarrhea vaccine tested for safety in 400 pigs at two different study sites and a rabies vaccine tested for safety in 665 cats at ten different study sites. No significant safety signal was detected.

When it comes to this RNA Particle vaccine platform, we are a far cry from an untested supervillain.

“The creatures outside looked from pig to man, and from man to pig”

Surveys report that four in five Americans support labelling of foods that contain DNA. These findings point at a significant scientific illiteracy. DNA is the molecule of life. All food we eat contains DNA, with exceptions like sugar, refined oils, salt, baking soda, and artificial food additives. Meat is made up of animal cells, which contain both DNA and RNA. Clearing up the misconception that food is DNA-free can help put the livestock RNA vaccines into perspective. These vaccines introduce a tiny strand of RNA into an animal that can only be alive because it is always transcribing its DNA into RNA and translating it into proteins.

But RNA vaccine fears are not simply built on a foundation of incomprehension. The vaccines are produced by industry and regulated by the government, but what if you distrust both? Already, anti-vaxxers are raising the spectre of Orwellian totalitarianism, of the government and industry working hand in hand to transform human DNA through the food supply, and if a person buys into this grand conspiracy theory, no amount of data is likely to dissuade them.

Moreover, it is all too easy for the anxious consumer to feast on the Nirvana fallacy. “Only a 100% safe vaccine should be authorized,” they might say. The hundreds of animals used in safety testing, then, are not enough and neither is the time scale. RNA vaccines had been in development for roughly thirty years when they were finally deployed in humans during the COVID-19 pandemic, but the technology was still perceived by many as too new. Those clinical trials hadn’t lasted long enough. Those who oppose their use in livestock will likewise request ten, twenty, thirty years of testing of individual vaccines, just in case something happens. It’s never clear what that something is, especially since delayed vaccine side effects tend to manifest within two months.

In the real world, risk-benefit analyses have to be conducted. The nimbleness of RNA-based vaccines comes from the fact that, in the face of a brand-new infection, they can be developed in eight to twelve weeks as opposed to five to ten years for a more conventional vaccine. This is because the capsule stays the same, and scientists can simply change the RNA instructions to code for one part of a new virus. In 2013, the swine industry was hit hard by a virus causing often-lethal diarrhea. This virus entered the United States in April of that year. Scientists had developed a candidate RNA vaccine the following month. It was field tested in August. Less than a year later, the USDA granted a conditional license to the vaccine. A fast and safe vaccine platform like this can save lives and help stabilize our food supply.

A parallel can be drawn with the annual flu shot. It is not, and could not, be tested every year in a long-term randomized clinical trial. Rather, when the original vaccine is updated for the current circulating strains, a smaller study is conducted and a supplement document is sent to the FDA to update the license. Otherwise, we would not have an annual flu shot: by the time one would be extensively tested for safety, the flu virus would have mutated, rendering the vaccine pretty much useless. Despite this small-scale testing of the flu vaccine, we have not seen catastrophic harm from it. And in the case of rare side effects, they simply cannot be seen in clinical trials since trials do not recruit millions of participants. For that, we have post-market surveillance, and the same applies to livestock RNA vaccines.

There is a silver lining, though, to the misinformation and fearmongering over RNA vaccines used in livestock. Mercola wrote, “I recommend avoiding all pork products” since he believes they “virtually all have been contaminated with the mRNA vaccines for the past five years.” Vegans and animal rights activists should rejoice. The reason given here is wrong, but they would argue that it’s a step in the right direction.

Take-home message:
- Anti-vaccine activists, including Joe Mercola, are claiming that RNA vaccines used in livestock are not tested for safety and could have negative consequences on livestock and on people who consume their meat
- The safety of these RNA vaccines has been tested extensively, by making sure that the virus used to transport the RNA cannot and does not make copies of itself, that the RNA cannot mess with the animal’s genome, that vaccinated animals do not shed these vaccine particles, that the virus capsule does not harm humans, and that the animals who receive these vaccines do not show signs of harm following their immunization


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