The smallpox vaccine saved hundreds of millions of lives. Arguably it qualifies as one of the most important inventions in history. But that doesn’t mean it was a welcome invention when it first came around.
Check out this cartoon apparently done shortly after Edward Jenner introduced his smallpox vaccine. The artist seems to imply that infecting people with cowpox will make them turn into cows. As this cartoon illustrates, there was actually some hostility towards the vaccine back when it was first introduced — ironic, given the smallpox vaccine may have saved more lives than any other medical intervention in history.
So as it turns out opposition to vaccines is as old as vaccines themselves — and as a quick search on Google will demonstrate, it’s alive and doing better than ever today. Admittedly, modern anti-vaccine activists no longer seem worried about their children turning into farm animals. Nowadays they make other arguments instead.
The most determined and capable anti-vaccine group in existence that I know of is the National Vaccine Information Center(NVIC). When I type “vaccine” into Google, the NVIC actually shows up on the first page of results. You can get a feel for the kind of information the NVIC offers from a brief trawl through their website, which turns up pages like this one by a Dr. Julian Whitaker, apparently a practitioner of alternative medicine.
Any doctor who assures patients that vaccines are completely safe is flat-out lying…Depending upon which vaccine is being administered, a single shot can contain a brew of adulterated bacteria, viruses, aluminum, mercury, formaldehyde, hydrochloric acid, and/or numerous multisyllabic chemical additives. To say that repeated exposures to such a wide range of toxins have no cumulative adverse effects on a child’s developing nervous and immune systems is more than irrational—it’s diabolical.
This paragraph — like the remainder of the NVIC website — is a noxious brew of fallacies and misinformation. Unfortunately, it’s misinformation of a particularly insidious kind, which is why these same arguments are repeated so often across the Web. The CDC has a list of the ingredients and reagents pharma companies use to manufacture vaccines at this link, and compounds like formaldehyde, thimerosal and various aluminum salts do indeed appear on it. But their presence is by no means as ominous as the NVIC would like you to think. To understand why, we have to think for a minute about how and why we make a vaccine.
I said in a previous post that Nature makes poisons more terrible than any chemist can invent. One of the best examples of Nature’s murderous skill is the bacteria that cause diphtheria, a deadly disease that used to be especially common in children. The Spanish called it “El Garrotillo”, The Strangler, and as recently as the 1920s, it caused 13-15,000 deaths in the US each year. The weapon these bacteria use to kill their victims is a large protein molecule called the diphtheria toxin (structure below).
The diphtheria toxin gets into your cells by sticking to a molecule on the cell surface, tricking the cell into treating it as legitimate cargo. Once inside, it gets broken up into pieces; one of these fragments catalyzes a reaction that shuts down protein synthesis, bringing the cell’s normal operations to a grinding halt.
We can fight diphtheria by taking advantage of your immune system’s built-in memory capability. The immune system has a remarkable ability to remember invaders it’s encountered previously. When it meets the same enemy a second time, it mounts a devastating response that prevents the invader from gaining a foothold again. If we can introduce your immune system to the diphtheria toxin, it can destroy the invaders before they make it past the shoreline.
It sounds nice in theory; but how can you arrange for your immune system and diphtheria toxin to meet? If I just inject you with straight diphtheria toxin, it would kill you rapidly. What we need is a way to inactivate the protein — to damage it so it becomes harmless. That’s why we treat diphtheria toxin with formaldehyde.
Formaldehyde is a much simpler and smaller molecule than diphtheria toxin — just one carbon atom, two hydrogens and an oxygen. Oxygen is more electronegative than carbon, meaning it tends to hog the electrons they share (think of it as an unusually selfish spouse). The oxygen is double-bonded to the carbon, so the carbon ends up very electron-poor, and the two wimpy hydrogens aren’t much help. So formaldehyde tends to act as an electrophile, an electron-poor molecule looking for love in all the wrong places. When you treat diphtheria toxin with formaldehyde, it reacts with relatively electron-rich nitrogen atoms in the protein, crippling it in a way that makes it harmless. Formaldehyde-treated diphtheria toxin is inactivated — it can no longer get inside your cells and shut them down. Your immune system, however, can recognize the inactivated protein and remember it for future reference.
Treating diphtheria toxin with formaldehyde is a clever solution to the problem, and in fact vaccine manufacturers inactivate tetanus toxin in the same way. We have to be a little careful, however, because the same reactive nature that makes formaldehyde useful also makes it potentially dangerous. It can react with proteins and DNA in your cells in just the same way it reacted with the diphtheria toxin. So formaldehyde is diluted during the manufacturing process, and the remaining quantity in the finished vaccine is less than 100 micrograms (100 millionths of a gram) per dose.
Formaldehyde in a vaccine might sound unnerving. Isn’t formaldehyde a toxic chemical? But toxicity is a more slippery concept than popular culture would have you believe. (See my earlier post, “What Does ‘Toxic’ Really Mean?”) When we talk about toxicity, there’s a number of things we have to think about — how does your body metabolize the compound, how quickly is it excreted, and how much is too much? There’s an old saying that “the dose makes the poison”, and it’s certainly true in this case, because small quantities of formaldehyde are being generated by ongoing processes in your body right now.
Your blood and tissues have a natural concentration of about 2.5 micrograms (millionths of a gram) of formaldehyde per milliliter. If you do the numbers, it turns out that a newborn baby’s bloodstream has over 10 times more formaldehyde than a vaccine at any given time. Moreover, your body metabolizes formaldehyde very quickly, converting it to formic acid and either excreting the formic acid in your urine or converting it to carbon dioxide. The tiny quantity of formaldehyde in a vaccine doesn’t hang around for very long.
At higher doses, formaldehyde can indeed be quite dangerous, but the amount you have in vaccines like DTaP simply isn’t large enough to be a problem. It’s a tiny fraction of the amount your body already generates and breaks down as a matter of course. Foods like meat and fruits naturally contain small quantities of formaldehyde and/or compounds your body converts to formaldehyde anyway, so your diet exposes you to far more significant quantities of formaldehyde than you get from a vaccine.
Aluminum & Acid
Dr. Whitaker also mentions hydrochloric acid as a “toxin” of concern. It’s an unfortunate argument, because it strongly suggests he’s being disingenuous. Either that, or he somehow skated through college and medical school while flunking general chemistry. Let me explain what he forgot to tell his readers — and I’ll keep it as simple as possible, so even Dr. Whitaker can follow along.
Hydrogen chloride is a simple molecule — a hydrogen atom stuck to a chlorine. When you put it in water it separates into a hydrogen ion* and a chloride ion. pH is a measure of hydrogen ion concentration; lower numbers mean more hydrogen ions and hence a more acidic solution. If I mix hydrochloric acid with a base, the base and the acid react and I end up with water and a salt. Mixing equal amounts of sodium hydroxide and hydrochloric acid, for example, gives me water and sodium chloride.
Imagine for a minute we have a public swimming pool with a pH that’s too high(i.e. too basic). Swimming pool pH needs to stay between 7.2 and 7.6, so you might add a little hydrochloric acid (aka muriatic acid) to bring the pH back down into the right range. Once you put it in the pool, the hydrochloric acid reacts with some of the excess base to make water and salt and you reduce the pH. The same is true when we use hydrochloric acid to adjust the pH of a solution in the lab, as for example when we manufacture a vaccine. The only thing that makes hydrochloric acid dangerous is the low pH of a hydrochloric acid solution. If you’ve mixed the hydrochloric acid with base and brought it back to a neutral pH, however, it is in no way dangerous — no more so than a glass of water with some table salt in it.
The aluminum salts play a much more interesting role. Manufacturers add salts like aluminum hydroxide to certain vaccines because they make vaccines more effective — you get a much more significant response to the vaccine. We’re not completely sure why that happens, although we have some theories about it. We do know, however, that you and I are exposed to plenty of aluminum as part of everyday life.
Aluminum is the third most abundant element in the Earth’s crust; it’s abundant in many types of soils, especially soils rich in clay. You consume small quantities of aluminum in the food you eat, and human breast milk contains aluminum on the order of ~40 micrograms per liter. Although aluminum can be dangerous in very high doses, any compound can be dangerous if you take too much, and there’s no reason to believe aluminum is dangerous at the level present in a vaccine, which are measured in fractions of a milligram.
Which brings us at last to the most controversial additive on Dr. Whitaker’s list: thimerosal. Its use in vaccines dates to the 1930s, and it was prompted by a series of nasty accidents with multi-dose vaccine vials. By sticking the needle through the rubber septum on the vial multiple times, nurses and/or doctors sometimes introduced bacteria by accident, and some children were inoculated with vaccines from Staph-contaminated vials. To avoid these lethal accidents, vaccine manufacturers began incorporating thimerosal as a preservative in multi-dose vials back in the 1930s, and starting in 1968 preservatives were required in multi-dose vials by law.
It’s worth pointing out the guidelines for the amounts of thimerosal in vaccines were based on methylmercury, even though thimerosal breaks down to ethylmercury in the body, and ethylmercury is excreted much more rapidly than its infamous cousin. (Nearly all fish and seafood contains traces of methylmercury BTW. Seawater itself contains mercury, albeit at extremely low concentrations.) Nor is there any evidence to suggest thimerosal was dangerous at the levels found in vaccines.
Right now, however, the safety of thimerosal is a moot point, because it’s been removed from pediatric vaccines as a precautionary measure. Currently there are no pediatric vaccines on the routine schedule that are manufactured with thimerosal as a preservative. Indeed, this has actually been true for some years now. The MMR vaccine does not and never did contain thimerosal. Some vaccines like influenza vaccine contain thimerosal, but there is a limited supply of thimerosal-free influenza vaccine available for patients who so prefer.
Given what we know about how vaccines are made, why do opponents continue to talk about “toxic chemicals” in vaccines? This is a tough question to answer. We can understand why vaccines might have aroused controversy in the early 19th century. After all, Jenner himself didn’t know for certain why vaccination worked; he just knew from experiment that it did. Today, however, we know a lot more about immunology. So why do vaccines elicit so much hostility? This part is just my opinion, but I think there’s a couple different things going on.
*The hydrogen ion actually gets picked up by a water molecule to make H3O+, the hydronium ion, but it’s the same general idea.
The first issue is greed, pure and simple. It’s ironic that alternative medicine practitioners often condemn the greed of the pharmaceutical industry, because many of them are just as money-hungry as the industry they criticize. Pharma companies cannot market a medication unless it has first been approved by the FDA, and the FDA regulations are the safeguard we have to punish them when they get out of line. When it comes to alt medicine practitioners like Dr. Whitaker, by contrast, there’s no such safeguard. Dr. Whitaker sells supplements that are regulated by much looser guidelines. He can make all kinds of vague, untested claims about his supplements so long as he tacks on the usual warning:
“These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.”
Dr. Whitaker, Dr. Mercola and other supplement-sellers stand to make money off the anxieties of patients and parents — and that’s why they spread this kind of misinformation. It’s unfortunate, but these people are unregulated, and it’s what they do.
The second factor is the media. We’ve all heard about the whole Wakefield-autism-vaccine controversy, which began with a single deeply flawed study published in the Lancet back in 1998. Now ask yourself this. Would you or I ever have heard of this study if it hadn’t been for some tragically gullible health reporters? Of course not. Many thousands of scientific studies are published each year, and most of us don’t read The Lancet. The media took Wakefield and made him into a public figure by mistake. Over the past few years the media has definitely come around, of course. Most articles you see on vaccines nowadays emphasize their safety. Unfortunately the damage has already been done.
The final reason is the most interesting one. I think vaccines are actually victims of their own success. They’ve done an incredible job of eradicating diseases that once killed or crippled thousands or millions of people. Neither you nor I know anyone whose child perished at the hands of El Garrotillo. Neither you nor I can remember friends or family who were crippled by polio or died of smallpox. Around the world, tens of thousands of babies die of neonatal tetanus or lockjaw every year, but it doesn’t happen in the US, so we don’t think about it. We take what we have for granted; we assume it was always this way.
Many people apparently see vaccines as “unnatural”, and we forget there’s nothing so natural as infectious disease. When we battle bacteria like C. diphtheriae, our enemy is Nature itself. Vaccines are the most effective weapon we’ve found in what would otherwise be an unwinnable war. It would be a shame to let complacency betray us into defeat.
There’s a really nice summary of the evidence on vaccines and autism at this link, by Jeffrey Gerber and Paul Offit. It’s free access, so if you’re interested check it out.
 FDA: Thimerosal in Vaccines.
 Paul Offit and Rita Jew. “Addressing Parents’ Concerns: Do Vaccines Contain Harmful Preservatives, Adjuvants, Additives or Residuals?” Pediatrics December 1 2003: 112(6), 1394-1397.
 Karen Broder, Margaret Cortese et al. “Preventing Tetanus, Diphtheria, and Pertussis Among Adolescents: Use of Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular Pertussis Vaccines.” Centers for Disease Control: March 24, 2006.
 Agency for Toxic Substances and Disease Registry: Aluminum, Relevance to Public Health.
 Sundeep Dhareshwar, Valentino Stella. “Your Prodrug Releases Formaldehyde: Should You Be Concerned? No!” Journal of Pharmaceutical Sciences October 2008: 97(10), 4184-4193.
Dhareshwar, S., & Stella, V. (2008). Your prodrug releases formaldehyde: Should you be concerned? No! Journal of Pharmaceutical Sciences, 97 (10), 4184-4193 DOI: 10.1002/jps.21319