Jailynn received her B.S. from the University of Oregon in biology and physiology. She currently studies protein biochemistry.
As millennials, we are becoming increasingly conscious about what goes into our bodies. Many of us favor food grown organically, if not home-grown. We advocate for the strict labeling of foods. We (rightfully) want to know what foreign compounds are added to consumer goods. We are in the midst of an era that questions everything, especially in the context of our own well-being. But what about questioning tried-and-true healthcare practices? To what extent are our reservations with the experts? And when do we trust the very infrastructure that has all but eliminated plagues that ravaged generations for millennia?
This article will highlight one of the chemicals found in vaccines (and other consumables) that has been on the receiving end of much scrutiny lately: formaldehyde. What is it? Why is it in vaccines? Is there actually reason for concern?
Here are the basics: formaldehyde is the name of a chemical compound (CH2O). You may recognize H2O as water but formaldehyde is much more than just a C plus an H2O. Here is the structure for any chemists out there (left).
It's simple and elegant if you ask me. Formaldehyde also goes by the name “methanal,” which I’m not sure is any less toxic-sounding. Formaldehyde got a bad wrap early on probably because of its pungent aroma and the fact that it is used in the embalming process (preserving bodies after a person has passed). The most common use of formaldehyde to date is actually its use in resins.
In researching this compound I was shocked at just how ubiquitous formaldehyde is to our surroundings. It’s everywhere: wood, paint, varnishes, and carpeting. I say that not to scare you but to emphasize that it’s more abundant than most people know. The average level of formaldehyde exposure by indoor air is estimated to be 0.5-2.0 milligrams daily. Keep this number in mind as we move forward.
Formaldehyde is not just a product of our homes; it is also a constituent of the upper atmosphere, produced during the combustion of methane. It is also a product within our own bodies when we synthesize amino acids. Amino acids are one of the most bio-relevant molecules; they are the building blocks of proteins, which we need to stay alive. There’s nothing different about the formaldehyde made in a factory and that produced by your body. It’s the same chemical structure. Your body recognizes formaldehyde and knows exactly what to do with it!
The average level of formaldehyde in the blood of an adult is about 2.5 micrograms per milliliter. An adult has a blood volume of 5 liters. That means, at any given moment, you have approximately 12.5 grams of formaldehyde circulating throughout your body. A similar calculation for an infant’s blood volume reveals 1.1 milligrams of circulating formaldehyde, still far greater than the largest amount found in any vaccine: the maximum exposure to formaldehyde in any vaccine is 0.1 milligrams. To be clear, one milligram is one one-thousandth of a gram. One gram is one one-thousandth of a kilogram.
So we know formaldehyde is fine. But why is it present in DTap (against diphtheria, tetanus, and whooping cough), polio, and other vaccines at all? Formaldehyde is found in trace amounts of some vaccines because it is a byproduct of the manufacturing process. It is used to deactivate bacterial products (such as toxins) which might otherwise make us sick. For example, tetanus is caused by a bacterial toxin wreaking havoc on the nervous system. The vaccine works by incorporating an inactive form of the toxin that the body can recognize to elicit a proper immune response. This inactive toxin does not cause disease, but it resembles the disease-causing toxin just enough to tell your body to arm itself against it. Formaldehyde’s job is to make sure the toxin is in fact inactive; otherwise, an injection of the active toxin would lead to actual tetanus disease.
If you have ever Googled “formaldehyde” you have likely seen reports that formaldehyde is a “known carcinogen to humans” according to the National Toxicology Program (NIEHS). Those words have caused quite the stir on the public health forum, and are echoed on many anti-vaccine websites. However, a headline rarely ever tells the full story. Delving into the toxicology report gives the following excerpt:
“Causality is indicated by consistent findings of increased risks of nasopharyngeal cancer, sinonasal cancer, and lymphohematopoietic cancer, specifically myeloid leukemia among individuals with higher measures of exposure to formaldehyde (exposure level or duration), which cannot be explained by chance, bias, or confounding.”
To translate, the “formaldehyde causes cancer” conclusion is based off of individuals who were exposed to abnormally high levels of formaldehyde for long periods of time. The people who fell victim to these cancers were typically occupationally exposed, such as embalmers and industrial workers. The amount of formaldehyde these patients were exposed to was much higher than the level found in any vaccine, which is barely a fraction of the natural amount in our blood. The precise dose of formaldehyde needed to cause cancer remains unknown, but suffice to say it is not on the level of ten milligrams, let alone 0.1 milligrams.
We witness campaigns every day that aim to avoid exposure to anything that has been linked to cancer in humans. Alcohol consumption and processed meats (e.g. bacon) have been linked to cancer. Physical inactivity, some infections, and pollution are all closely linked to carcinogenesis. Some risk factors are avoidable, some are not. Unfortunately, carcinogens are everywhere. Consider skin cancer: just because high exposure of the sun’s UV rays is known to cause cancer doesn’t mean that 1) it will happen to you, or 2) you should never ever go out into the sun. And that brings me to my final point: as with anything in life, too much of anything is never a good thing. In diet, exposure, and questioning the experts, moderation is key.