What is Natural Immunity? Part 1
Author: Ryan Hassan, M.D., Boost Oregon's medical director and pediatrician working at Oregon Pediatrics in Happy Valley.
In the conversation about vaccines, one concept that comes up frequently is the idea of “natural immunity”. Anti-vaccine propaganda often features this term heavily as a way of contrasting the immunity your child gets from a disease by getting sick from it, with the immunity they get from a vaccine. The anti-vaccine lobbyists argue that “natural immunity” comes from natural infection with a disease, and the fact that it’s natural means it’s somehow better. The implication is that immunity following vaccination is somehow “artificial”, and therefore inferior. Let’s take a look at the problems with this idea.
The first, and most obvious point, is that this argument relies completely on the naturalistic fallacy. This is a common fallacy in human thinking that leads us to believe that if something is natural, it is necessarily better; whereas things that are “unnatural”, or manmade, are harmful. This idea is appealing to people who value nature, and the many benefits it provides; particularly for those of us who appreciate things like the taste of homegrown food, and the sustainability of natural cleaning products. As humans, when we see the clear benefits of specific naturally-occurring resources, our pattern-seeking brains try to find a unifying explanation for why those things are beneficial, and the obvious conclusion is that they are all natural, so therefore it must be true that natural things are beneficial in general. This is one of many examples of how our prehistorically-evolved brains’ innate predilection for pattern recognition can be counterproductive in the modern world.
As Nassim Taleb explains in his book, The Black Swan, European bird enthusiasts used to think that all swans were white, and their evidence for this was that they had only ever seen white swans. Of course, this was completely wrong, but no one had any way of knowing this until someone saw a black swan. They were only looking for evidence that confirmed their beliefs, so every time they saw a white swan, they would think, “there goes another white swan; that just further proves that all swans must be white.” Similarly, people who avidly ascribe to the naturalistic fallacy will look for all the “natural” things they can find that they think are beneficial for them, and point to those things as further proof that natural things are good.
When one tries to take the opposite approach, though, and disprove the idea that all natural things are good, it quickly becomes clear that there are plenty of things in nature that we want no part of. For example, rape, incest, infanticide, and patricide are all seen in nature, but that is hardly a defensible justification for a human to commit any of those acts. Similarly, there are thousands of naturally occurring toxins and poisons that are lethal to humans, including botulism, which is the most toxic substance known, and is found in dirt and honey. In fact, there are almost no aspects of our lives that could reasonably be considered “natural”. We live in human-made homes, mostly get around in human-made vehicles, walk on human-made paths while wearing human-made footwear, and read blog posts written in human-made alphabets expressing a human-made language on human-made computers, which we carry around all day in the pockets of our human-made clothing. The “paleo diet”, so-named because it purportedly mirrors the diet of paleolithic humans, consists of exactly zero foods that would ever have been eaten by paleolithic humans; because every plant and animal consumed by humans in the 21st century is the result of thousands of years of genetic modification through human selection (here's a fun article that talks about this idea more). With all of these “unnatural” things in our lives, why would it make any sense to single out vaccines as the “unnatural product” that we want to cut out of our lives, when they are the product most likely to protect us from health problems and least likely to cause us harm?
