69 Doses and Matters of Trust

The other day, I wrote about the incorrect claim that there are 69 doses of vaccine on the U.S. recommended childhood immunization schedule. That claim has morphed into 71 (or 72 [Edited to Add (2/24/15): apparently, anti-vaccine groups are now dishonestly claiming 74!]) doses since the publication of the 2016 schedule, which added the Meningococcal B vaccine for at-risk individuals, as well as those for who would like to get the vaccine and their doctor agrees it is indicated. The MenB vaccine has not yet been added as recommended for all individuals. At any rate, I had hoped that my post might help those repeating the "69 doses" claim realize that they were mistaken and misled by whomever they heard the claim from (e.g., @VaxCalc has been quite busy on Twitter, spouting out that claim on an almost daily basis, despite being told that it is incorrect). I've share the post with a number of people on Twitter that have repeated the claim. As yet, I have not had a single person admit that the claim is wrong. Mostly, they try to come back with rationalizations, which really misses the point of my post.

So what's behind the misunderstanding? What point was I trying to make?

First, let me address where I think the misunderstanding originates. There are two terms for which it is vital that we have a clear understanding and definition, so that we all use the same meanings for word. I've written before about how some anti-vaccine activists like to redefine words to fit their message. This is another situation where I think that is happening. With that in mind, let's take a look at these words:

• Dose - in medicine, a dose is simply a specific quantity of medicine to be taken at one time. In the context of vaccines, a dose of vaccine is one administration of the vaccine. Which brings us to the next term.
• Vaccine - a vaccine is a preventative medical treatment consisting of one or more types of viral or bacterial antigens, as well as the diluent, or vehicle. The diluent is all of the non-therapeutic "stuff" in the vaccine: water, stabilizers, adjuvants, manufacturing residuals, and so on. For example, the Hepatitis B vaccine contains HepB surface antigens, an aluminum adjuvant, the liquid vehicle, etc. for a total dose of 0.5mL. Similarly, the DTaP vaccine contains diphtheria antigens, tetanus antigens, pertussis antigens, an adjuvant, liquid vehicle, and so on for a total dose of, again, 0.5mL.

One dose of vaccine means (for injected vaccines) a single injection of 0.5mL. A shot of the Hep B vaccine is one dose. A shot of the DTaP vaccine is also one dose. A shot of DTaP-HepB-IPV (diphtheria, tetanus, acellular pertussis, hepatitis B, and inactivated polio) is one dose.

Where is the misunderstanding? For that, let's look at the originator (or at least, one of the main promoters) of this false claim, the National Vaccine Information Center (NVIC). They created a poster specifically for this claim, reproduced here:

Click to enlarge.

Another variation on this is this meme:

Click to enlarge.

NVIC misleads people with this poster by stating that, for example, DTaP vaccine is actually three separate vaccines, simply because it contains antigens for three different diseases, while ignoring that fact that the total number of antigens in the schedule has gone down dramatically, as I showed in my other post. But at the same time, they note that a vaccine has all of these other allegedly "bad" ingredients. In other words, they imply that your child will get three separate injections of 0.5mL, three separate needle sticks every time they go in for their DTaP or Tdap boosters. The same thing with MMR. But as I noted in my previous post, the total number of doses of vaccines is significantly lower than NVIC would have you believe. It is even lower if one opts for combination vaccines, like the DTaP-HepB-IPV vaccine.

But what's the point? Why does it matter if it's 69 doses of vaccine, 53 doses, or only 46 doses? First off, that is, at minimum, a difference of 16 injections. NVIC is inflating the number of needle sticks by anywhere from 16 to 23 shots! I am all for reducing the number of times kids need to get a shot. Getting a shot hurts. We can do things to help reduce that pain (e.g., distracting the child, getting them to relax, etc.), but there's always going to be some discomfort. It can also be an emotionally distressing event if the child is afraid of needles. Use combination vaccines where there are safe and effective options. What NVIC is doing here is frightening parents by suggesting that their children will have more needle sticks and more trauma than they really will.

The other point that I want people to get is this: the "69 doses" claim is wrong, and very easily shown to be so. Whether NVIC and the others who actively promote this claim to their followers are doing so out of simple misunderstanding or are deliberately lying in order to advance their anti-vaccine message is largely irrelevant. What matters is that they are wrong about this. And if they are wrong about something as simple as how many doses are in the vaccine schedule, what else are they wrong about? Are there other claims they make that are based on misunderstanding or outright lies? If they so easily make a mistake about the number of doses in the vaccine schedule, how much easier is it for them to be wrong about more complex issues?