Tuesday, November 2, 2010

Vaccine Awareness Week: I'm not Anti-vax, I'm Pro-Safe Vaccine

This whole Vaccine Awareness Week has got me to thinking a bit about some of the arguments that anti-vaxers make. I wonder just how they reason things out. What is it that resonates so strongly in their minds that they don’t simply question vaccines, but go so far beyond reason and rational thought? They can look at the very same things that those of us who accept vaccines view as amazing advancements of medical science and instead see all manner of bogeymen. Every last thing to do with vaccines, if you believe many of them, is the epitome of all that is vile and evil. The really incredible thing, though, is that even while they have a knee-jerk reaction to reject any and every vaccine, they insist that they are not anti-vaccine. Rather, they say that they are “pro-safe vaccine.”

As I thought about this, I realized something: I, myself, am not anti-vaccine; I’m pro-safe vaccine.

That’s right. I actually agree with anti-vaxers, just not in the way that they might think. That phrase, “I’m not anti-vaccine; I’m pro-safe vaccine,” applies to me quite well, and I imagine that quite a number of my fellow skeptics would agree that it applies to them, too. In fact, I feel that that phrase is more descriptive of those who support vaccination than it is for the majority of anti-vaxers who say it.

What do I mean by that?

Well, clearly, since we support vaccines, we’re not anti-vaccine. The only exception to that, though, is when the risks – the true risks – outweigh the benefits. Let’s take a look at polio and its vaccine as an example.

Polio is caused by a virus that, for most people, causes no symptoms, but can still be transmitted by someone who is infected. A little less than 1% of victims (1 out of 100) will have their limbs, typically their legs, paralyzed by the disease. Of those, around 2%-20% will die (PDF) due to paralysis of the muscles used for breathing. Those who are fortunate to recover still face permanent disability or disfigurement.

Before there was a vaccine, tens of thousands of cases were reported every year in the U.S. Entire wards of hospitals were filled with iron lungs to try to keep alive those whose respiratory capacity was diminished by the virus. Then along came the oral polio vaccine (OPV).

OPV used a live, weakened polio virus and was nearly 100% effective in producing lifelong immunity. OPV had the added benefit that immunity could be passed on to close contacts who were not directly vaccinated. This makes it a very good choice for regions with high polio rates and low immunization rates. The drawback, though, is that it has the potential to cause vaccine-associated paralytic poliomyelitis (VAPP) in about 4 per 1,000,000 (PDF) vaccines, as well as to mutate into a virulent form that spreads through the population.

Developed around the same time as OPV was the inactivated polio vaccine (IPV). IPV does not have the risk of VAPP that comes with OPV, but it is less effective (~80%-90%) and does not spread immunity to others. In regions with lower rates of polio and higher vaccine uptake, IPV is the safer choice. It is largely for these reasons that the U.S. stopped using OPV and switched entirely to IPV; the OPV risks do not outweigh the benefits, in contrast to the IPV. We have switched over to a safer vaccine.

I also fully support the 1999 withdrawal of RotaShield, a rotavirus vaccine that had a 1 in 10,000 risk of intussusception. Due to the potentially fatal outcome of intussusception and the rate at which it was likely to occur, the risks of RotaShield outweighed the benefits derived from the vaccine.

Part of the problem, I think, is that antivaxers tend to have a poor grasp of the relative risks of diseases and the vaccines that prevent them. For example, measles tends to be viewed as a harmless childhood disease that results in a week or two of misery, then the kid is all better. The vaccine, by contrast, is viewed as a horrible product that causes all manner of ills (usually tied to autism). But when one looks at the research conducted by many unrelated individuals all over the world, we see a different picture. Measles carries a risk of pneumonia in 6:100 infected, encephalitis in 1:1,000 and death in 2:1,000. The most common adverse effect in MMR recipients is a local reaction. Severe allergic reaction or encephalitis occurs in about 1:1,000,000. In other words, any individual is 1,000 times more likely to develop encephalitis if infected with measles than if they are vaccinated.

Another aspect of the “I’m not anti-vax, I’m pro-safe vaccine” line is that antivaxers tend to view all of the various chemicals used in the making of the vaccine as an unacceptable toxin, even if the chemical is no longer in the final product in any meaningful amount. Ask how vaccines can be made safer, and they will say, “Remove the toxins.” Nailing down just what toxins they mean is a far trickier part, particularly since many seem not to understand the concept of “the dose makes the poison,” nor indeed the purpose of the chemicals used. Let’s take formaldehyde and thimerosal as two examples.

Formaldehyde is used in the production of vaccines to inactivate the bacterial toxins and viruses, as well as to stabilize the antigens used. Much of the formaldehyde that is used during production is diluted out, so the final vaccine contains only trace amounts. Much of the fear surrounding this probably comes from fear that it may cause cancer, mixed with the view that it has been used for embalming, as well as industrial uses in the manufacturing of textiles. What is less commonly known is that formaldehyde is a common byproduct of metabolism. Your body produces it to break down other chemicals and to synthesize proteins and nucleic acids. So, in small amounts, it is very important to the functioning of your body. True, exposure to large amounts can cause health problems, but this illustrates how the dose makes the poisons. Just the Vax has a very nice write-up on this.

Thimerosal is another commonly encountered “toxin” topic. Thimerosal is a mercury compound used as a preservative. The fact that it is in any way related to mercury is, I believe, the reason for the uproar among the anti-vax community, the thinking generally going like this: Mercury is bad. Thimerosal contains mercury. Therefore thimerosal is bad. I wrote about this a little bit over at The Truth About the Evils of Vaccination. Again, large amounts of this substance can be dangerous. However, in regions where multi-dose vials of vaccines are used, and where proper storage techniques are either unavailable or cost too much, preservatives like thimerosal are needed to prevent the growth of contaminating bacteria or fungi, which pose quite significant health risks. Couple the risks from contamination and the general safety of thimerosal (no known cases of adverse health effects in the amounts and route of administration found in vaccines), and the benefits of its use outweigh any risks involved. However, where its use is not necessary, where the production costs associated with single-use vials and proper storage equipment are not an issue, then there is no significant reason to use it in the final formulation that is administered to individuals. In the end, I agree with moving toward getting rid of thimerosal in vaccines, not because it is some horrible toxin, but because it simply isn’t needed anymore.

We should always be striving to make all of our medical products safer. We will never achieve the utopian 100% safety, but we can get pretty darn close. If a vaccine causes reaction X in 1 out of every million individuals, let’s see if we can make that 1 per 10 million. But in doing so, we must keep things realistic. What are the real risks involved? How do they weigh against the risks from the disease being prevented? We need to pursue the actual risks, not what we imagine are the risks. Although we should never settle for substandard products, we need to rely on science and objective facts, rather than emotion.

That is why I am not anti-vax, I’m pro-safe vaccine.

2 comments:

  1. Good post Todd. I find it astonishing that the 'I'm not anti-vax, I'm pro-safe vaccines' camp have decided that sceptics are inherently 'vaccine-injury denialists' (right out of ol' Stagmom's mouth).

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  2. Well, since we don't accept that vaccines cause autism, then we must be vaccine injury denialists. But, why let reality get in the way of a good ol' poisoning the well?

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