Friday, February 2, 2007

So why DO you vax?

I've found MDC to be a fairly interesting place and full of lots of information. It is somewhere that has an abundance of AP information. Now, I'm a huge supporter of Dr. Sears and his ideas on AP. I love the ideas and his writing style (something hugely important to me is a person's writing style - I will avoid certain author's because of it, but I digress). Unfortunately, like anywhere on the www you get people who are fanatic about things. That goes for every area. It's a "my way is the ONLY way and if you don't do this you're a horrible, awful parent and person!" mentality. One of the boards the really bothers me is the vaccination board, which is ardently anti-vax. As in no child should be vaccinated for anything, ever because vaccinations are toxic, horrible things that kill people and anyway they don't work so why bother exposing your child to toxic chemicals.

As a scientist, I am somewhat aghast at this POV. Not because I think all vaxes are safe and they should be given willy-nilly. In fact, I think that there are far to many given very early on for things that an infant is probably not likely to contract. That aside, there are a lot of debates on that vax board and one of the most commonly asked topics is why do you vax. Another web group I'm a part of has a lovely woman posting on it who wrote a wonderful succinct reply to this question. With her permission, I am reposting it here.

To preface this a little, it is a common attack point with anti-vaxers that people who are pro-vax (i.e. anybody who would be insane enough to ever vax their child for ANYTHING!) can never provide "a single link" to back up their reasons. Now being a scientist and knowing scientific method backwards and forwards, let me just also point out that basing a decision (especially one that important) on ONE of anything (be it a study, a doctor's opinion, your best friend Sam or whatever) is not the way science works. The more, the better is a scientist's belief and that's true for vax studies as well. But the discussion goes on from there...

I've been thinking about the anti-vaxers' insistence that they depend on science, peer-reviewed studies, etc, and that pro-vaxers "can't provide even one link"of reasons to vax. I think there's a pretty vast misunderstanding of how scientific research happens and is reported. No, there's no ONE study that will convince EVERYONE that vaxing is in our best interests. There are, of course, hundreds -thousands! - of studies on vaccines. Personally, I've been reading about Prevnar recently. There are studies on how well it works, how it should be scheduled, what the effects of it are on children,what the effects of vaxing children are on adults,what the effects of it are on individual communities,what kinds of adverse reactions there are, and so on. Looking at a range of studies, you can get an excellent sense of what the impact of this vaccine is on both an individual and a public health level, andyou can make your choice as to whether you feel it's a positive impact (obviously, that's where I lean, andthat's where most of the medical establishment leans). There isn't ONE study on Prevnar. There's a constellation. For older vaccines, there are galaxies. I'm really not sure, when we're told "Show me just one link!" what we're being asked to prove.

Of course, it helps to be able to comprehend whatyou're reading. For people like Mama In The Boonies, what's going on is simple incomprehension. In the recent thread, she saw something in the package insert for Hib that declared that there were zero serious adverse reactions to the vaccine in one particular age cohort, and somehow was confused enough by the sentence structure to think it was arguing that the number of serious adverse reactions in the overall study group was near 80%. Simple - perhaps willful -misreading.

But there is more complex misreading going on. When researchers write up their findings, they explain their methods, including potential weaknesses of thosemethods and ways in which the data may be flawed. No one writes a study in which they claim 100% confidence in their results. How does that play out when we'retalking about vaccines? Well, say there's a study in which someone is evaluating adverse reactions to the MMR. Perhaps they find 15 people who have grown a third eye in the middle of their foreheads, and they have evidence that this is the result of the MMR. Youare then going to see a section in the study that goes something like this: "Perhaps there are more than 15 people who grew a third eye after the MMR. Here are some ways we may have overlooked third-eye sufferers, or ways in which third-eye sufferers are underreported. On the other hand, perhaps there are fewer than 15 people who grew a third eye after theMMR. Here are some ways this condition could be over-reported or misinterpreted." So, you see whereI'm going with this. Anti-vaxers are going to then EXPLOIT THE INTEGRITY OF THE SCIENTIFIC METHOD by taking the part of the study where the scientist admits that third-eye-sprouting could be underreported, and claiming that as the main conclusion of the article.

Similarly, there is language on package inserts which all medications which have not undergone certain kinds of testing must include. You'll often see anti-vaxers quote something about how this or that vax has not been tested for "carcinogenic, fertility, or mutagenic properties." That doesn't mean they make everyone infertile, gives them cancer, and turns them into blue elephants. It means certain kinds of tests, such as tests on pregnant women, haven't been done. If you look at the prescribing information on many widely accepted drugs, you'll see similar language. So, government regulations which protect us by not allowing drug-makers to make unsubstantiated claims, actually feed paranoia (not that I'm saying those regulations are a bad thing!).

Another reason anti-vaxers feel comfortable claiming the science is on their side is that in the sheer number of studies out there, there are going to be some which support a more skeptical view of vaccines.It's not that those studies do not exist. It's that those studies need to be balanced in the context of the field as a whole. For example, there may well be a study which finds a link between MMR and Third-Eye-Disease. There may also be ten more studies which find no connection. So, what's an anti-vaxer to do? Say, "Hmmm, I'm very concerned about third eyes. Clearly, someone has found evidence for a vax-third-eye link. At the same time, there's evidence against it. I'm not sure. I'm going to look at ALL the studies and see which are most well-designed and conclusive." Or is the anti-vaxer going to say "Well, duh. Vaxes cause third eyes. Ihave a study right here that proves it." The more unfamiliar with science you are, the more likely you are to think that a single study is conclusive -because, you know, it's a STUDY! Wow! (And I speak from personal experience, as a non-science-person who is just beginning to be able to make sense of some of this stuff.)

Finally, we can't ignore that there ARE validcriticisms to be made of vaccine policy, and there ARE legitimate fields of inquiry when it comes to possible problems with vaccines. The problem is, integrity requires that those of who approach the subject without fanaticism will give the other side its due -such as I've done in the preceding sentence! It's very, very rare that anti-vaxers will do the same.

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