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Home » Germ theory denial – another favorite of the anti-vaccine world

Germ theory denial – another favorite of the anti-vaccine world

I have been meaning to write about germ theory for years because a big part of vaccine denialism requires a good bit of germ theory denialism. Some anti-vaxxers want to create an illusion of scientific integrity by attempting to outright reject the germ theory of disease.

Germ theory is one of the central tenets of biology along with biochemistry, cells, evolution, and genetics. It is not some idea that was invented by those of us who support vaccines just to convince people to get vaccines. It is a foundation of medicine and biology that is centuries old.

This article is going to be a discussion of what exactly is germ theory, and briefly show how the anti-vaxxers deny it to “prove” that vaccines are unnecessary.

cutout paper composition of antiseptic gel above bacteria germ theory
Photo by Monstera on

What is a scientific theory?

Before we can even start, we need to discuss what constitutes a scientific theory. At its core, scientific theories describe the mechanisms (causality) of observed phenomena. The core component of a scientific theory is that it can provide explanations and predictions of similar phenomena that can be tested through the scientific method.

In this context, a theory is not a random guess, which is how many lay people think of the word. This has led to years of “evolution is just a theory” dismissals from creationists. I’ve read the same thing about germ theory.

However, scientific theories are not “written” by one person, they result from huge bodies of scientific research produced over long periods of time. Theories rest upon the writings of numerous contributors over time and are supported by vast amounts of evidence.

One person, even a Nobel Prize-winning biologist, cannot “invent” a theory. Usually, a theory evolves (sorry, couldn’t resist) from initial observations into hypotheses through scientific consensus to an accepted theory. Each step requires more and more evidence – a scientific theory, like evolution, is based on a literal mountain of evidence.

This process of scientific knowledge occurs over a continuum, and it may be impossible to point out the exact date the theory appears. The evolution (sorry again) of the evidence supporting scientific theories is based on the scientific method. As more and more data is gathered from the scientific method, the scientific theory slowly gains support in the scientific community.

Furthermore, scientific theories are used to make predictions about the natural world. This predictive ability is not a pseudoscience like a psychic telling you who to marry, it is the ability to use the scientific method to question a prediction about a future result (say man evolving a fifth limb), and answer it. If the theory of evolution predicts that fifth limb, but the prediction fails through a scientific study, then the theory gets revised.

Evolution is an observed fact – there are millions of published papers and books that describe these observations. We can observe evolution in everything from the fossil record to how viruses cause a pandemic (SARS-CoV-2 is a perfect example of evolution). Let’s make this clear, evolution is a fact.

On the other hand, the “theory of evolution” explains the mechanism (thus, the ability to predict) of evolution. Currently, the two best explanations of the mechanisms of evolution are natural selection and genetic drift.

The fact of evolution is supported by overwhelming evidence. The theory of evolution is supported by overwhelming evidence.

But as I always say “scientific ideas are always provisional.” If someone were to publish evidence, and by evidence, I mean high-quality evidence published in respected biomedical journals, then we might reconsider the fact and theory of evolution.

For example, there is a joke that evolution might be overturned if we found a rabbit fossil in a rock layer far earlier than when mammals evolved. But would that refute evolution? Not really, maybe it was an error in determining the age of the rocks, or our rock aging science needs revision. Or maybe, mammals evolved earlier than we thought. Or an alien visitor, intelligent rabbits, visited our planet 1 billion years ago. But finding a rabbit in some rock strata way below the point where rabbits evolved probably would not affect the theory of evolution.

So, when we say “theory” in biology, it is not a guess. It is not an idea that pops into someone’s head. It is the pinnacle of scientific principles.

a woman doing an experiment germ theory
Photo by Kindel Media on

What is the germ theory?

Now that we’re clear that scientific theories are not just random guesses, let’s discuss what is the germ theory of disease. It states that living microorganisms, such as bacteria, protists, or fungi, and non-living organisms like viruses and prions, all known as pathogens, invade humans and can lead to disease.

Diseases that are caused by these pathogens are called infectious diseases. And just to be clear, not all diseases are caused by infectious diseases For example, cancer is mostly not caused by microorganisms, although the human papillomavirus (HPV) and hepatitis B, viral pathogens, are linked to many cancers.

The germ theory of disease had its birth in the late 1600s when physicians began to suspect that invisible (to the naked eye) organisms caused some diseases. With the advent of the microscope, scientists began to understand the basics of germ theory.

By the 1700s, scientists began to find these microorganisms that caused diseases by using early microscopes. They didn’t know what they were observing, but there was a link. And by the early 1800s, they could identify specific microorganisms that caused diseases. Edward Jenner, using observations of those who contracted cowpox and were immune to smallpox, developed the first vaccine – this is probably the first application of the germ theory of disease to clinical medicine.

Louis Pasteur is considered to be one of the first proponents of the germ theory of diseases. His experiments showed that diseases could be prevented by killing or stopping germs – this directly supported the germ theory along with its application in medicine. Of course, he is best known to the general public for his invention of the technique of treating milk and wine to stop bacterial contamination, a process now called pasteurization

In modern medicine, we have a logical methodology to determine whether a disease is caused by a microorganism – Koch’s postulates. our criteria are designed to establish a causative relationship between a microorganism and a disease:

  1. The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.
  2. The microorganism must be isolated from a diseased organism and grown in pure culture.
  3. The cultured microorganism should cause disease when introduced into a healthy organism.
  4. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.

Once again, the germ theory is not just a random “idea” pushed by some scientist 150 years ago – it is based on a wealth of evidence over that time. There are over 2000 articles that use Koch’s postulates to show causality between microorganisms and diseases.

Still, some quacks think that the germ theory is nonsense. They reject it not with evidence but with their opinion.

Photo by Artem Podrez on

Why do anti-vaxxers deny the germ theory?

Getting into the brains of anti-vaxxers to see why they do anything can cause undue harm to my neurons. However, I think there are two reasons:

  1. Without germ theory, vaccines have no purpose.
  2. Without germ theory, they can blame something else for causing the disease like a bad diet or toxins.
  3. Without germ theory, the grifters can sell miracle supplements to treat what they believe is the real cause of the disease because germs don’t exist.

Oh, I’m sure there are other reasons for rejecting the germ theory, but those are what hit my cynical brain. Now, what you’ll notice with these people is that kind of pick and choose when they accept or deny the germ theory.

For example, COVID-19-19 has brought germ theory denial to the forefront. Instead of accepting that a novel pathogen, SARS-CoV-2, could cause disease and death of millions of immunologically naive people, some want to believe it’s something else. So, instead of accepting the science, the anti-vaccine world is using misinformation, conspiracy theories, and utter nonsense to convince people that it’s a fake disease and that vaccines are useless.

Germ theory denial used to be on the fringe of the pseudoscience crowd, but COVID-19 has brought it to the forefront. People are rejecting germ theory like creationists reject the theory of evolution because of reasons.

So what do these people think cause COVID-19? They make wild claims that we haven’t been::

  • maximizing our nutritional status
  • minimizing our toxicity status, i.e. detoxification
  • maintaining a proper pH or acid/alkaline balance
  • maintaining a proper energetic/electrical balance
  • cleansing our bowels

David Gorski, MD, recently wrote a massive article on the history of germ theory denial and how it’s led to some weird stuff about COVID-19. Here’s one of my favorites:

This was Kaufman’s first claim, namely that SARS-CoV-2, the coronavirus that causes COVID-19, is not a virus at all, but in fact exosomes that are removing the “toxins” that are the “real” cause of COVID-19. What are exosomes? In brief, they are small extracellular vesicles (like bubbles) that bud off from cells and can bump into and fuse with other cells.

In any event, Kaufman claims that what is seen on electron microscopy is not a coronavirus, much less SARS-CoV-2, but rather exosomes. It does beggar the imagination that so many virologists and electron microscopy would make such a fundamental mistake, but Kaufman does seem to be arguing that. Specifically, as Frank Visser points out, his argument really is as simple as observing that the coronavirus resembles an exosome plus adding the claim that what PCR is detecting is RNA in exosomes, not the coronavirus, as his slide above states.

No, it does not.

Let’s go back to Koch’s postulates, and apply them to COVID-19:

  1. The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms. Done.
  2. The microorganism must be isolated from a diseased organism and grown in pure culture. Done. This is why we got vaccines so fast — a laboratory in Australia isolated the virus and scientists could sequence the genes of the virus.
  3. The cultured microorganism should cause disease when introduced into a healthy organism. Done. Of course, we haven’t deliberately infected humans, animal models were used and we observed the disease after the introduction of the virus.
  4. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent. Done.

Dr. Gorski concludes his article concerning COVID-19 with this:

Germ theory denial is not a new phenomenon. It’s been around as long as germ theory has and has long been a major strain in alternative medicine beliefs about disease. Pre-pandemic, the attractiveness is that “terrain” theory allowed its believers to labor under the delusion that, if only they ate the right foods, lived the right lifestyle, did the right things, and were, from a health standpoint, virtuous, they would be virtually immune to infectious disease.

My favorite example occurred when Bill Maher claimed that his diet and lifestyle (but what about his copious use of weed?) meant that he couldn’t catch the flu on an airplane even if there were several people with the flu on the flight, to which Bob Costas retorted acidly (word choice intentional), “Oh, come on, Superman!” It’s all of a piece with what I like to call the Central Dogma of Alternative Medicine, namely that you have virtually 100% control over whether you get sick and if you just want to be healthy badly enough you will be.

Of course, as I said before, these days most germ theory denial is not absolute. Far more often, germ theory denial is “soft” in that it takes the form of a (usually weak) concession that microbes can under certain circumstances (basically only if the host is already sick) cause disease, but with the caveat that the disease is so much less likely to take hold or so much less likely to be deadly if you only live a virtuous life in terms of diet, exercise, and lifestyle; i.e., if you are Superman in terms of health. Unsurprisingly, it is the latter claim that nearly always overshadows the concession.

There is, of course, a grain of truth here in that debilitated people and people with comorbidities are far more likely to die of COVID-19 (for example), but in the hands of “soft deniers” of germ theory that grain of truth results in the delusion that they can’t get seriously sick from COVID-19 because they are so healthy and that they are thus not a danger to those who are particularly susceptible to coronavirus. This “soft” germ theory denial also leads to massive victim shaming, such as when Del Bigtree urged his listeners to “catch this cold” (COVID-19) to gain “natural immunity”, even as he blamed those at risk for death from coronavirus for having lived an unhealthy lifestyle that had put them at risk.

It also leads to ideas that border on eugenics, such as the Great Barrington Declaration, which recommends basically letting COVID-19 rip through the “healthy” population while using “focused protection” to protect the vulnerable. Never mind that COVID-19 can kill the healthy and that it’s impossible to isolate the vulnerable from the virus while it’s spreading exponentially in the general population. Finally, this “soft” germ theory denial provides a reasonable-seeming pretext to oppose masks, any sort of “lockdown”, and, of course, vaccines.

See, they pick and choose when it benefits them. Or they modify the germ theory to fit their needs. They continue to claim, after millions of deaths, that COVID-19 is relatively harmless, nothing more than a cold. So a cold virus is a real thing, but the COVID-19 virus doesn’t really exist.

Yes, it’s frustrating.

close up view of an experiment
Photo by Kindel Media on


It’s important to understand that one should not conflate the pathogen with the disease. HIV, the pathogen, causes AIDS, the disease. Varicella zoster, the pathogen, causes chicken pox and shingles, the diseases. Whenever I write articles about diseases, like cervical cancer, I discuss how the pathogen, HPV, is linked to cervical cancer. This is the fundamental part of the germ theory.


Michael Simpson
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