Swimming through the thimerosal

Whoa. (Another Keanu Reeves moment.)

I had a sneaking suspicion when I posted it that I might have stepped into it yesterday with my cranky little rant. And step into it I did. My article was linked to from Pharyngula, a Daily Kos discussion thread, the Captain's Quarters, the Evidence of Harm discussion boards, and even a Democratic Underground discussion thread (where, depressingly there were quite a few people ranting about how the mercury-autism connection is being "covered up"). Yesterday set all time records for the number of hits in a single day to this blog. It's still strictly small stuff as far as the big bloggers go ("Ptooi! I laugh at your measly 2,100 hits in a day!"), but for me it was big. Any time you take on the mercury/autism crowd, particularly in such a combative fashion, you have to be prepared for some even crankier responses. In retrospect, perhaps I should have been less combative, but sometimes I just have to vent. Strangely enough, though, the negative reactions were actually fewer than I expected and the positive reactions more numerous, and the really strongly negative reactions were way fewer than I had expected.

There are too many responses to respond to each individually, but they seemed to fall into categories. Several suggested that I tighten this up and send it to Salon.com. I'm flattered. I assume it would probably be necessary to remove the scatalogical references referring to the article as a big dripping turd, but I could do that. Indeed, I was considering doing just that until I saw some of the letters to the editor that have already shown up at Salon.com. One was from Kathleen Seidel, who runs the website Neurodiversity.com, and you should read the letter in its entirety. As for the others, these guys were just as hard on RFK Jr. as I was. Some examples follow.

Lisa Randall:

What about the Geiers, who claim to have found fantastically high rates of autism among children who received thimerosal? Would that be the same Geiers who had never even heard of SAS, a basic tool of statisticians, before encountering it at the CDC? The same ones who print their "work" in vanity press journals and have been roundly debunked by not only the Institute of Medicine but also the American Academy of Pediatrics and other academic researchers? The father who is a gynecologist-geneticist and the son who runs a consulting business helping people sue doctors?

Thanks, Lisa. I had forgotten about the Geiers' inability to use SAS. That was truly amusing when I found out about it. Let's also not forget their attempt to compromise the confidentiality of patients in the CDC database, either, or that David Geier's company exists mainly to sue vaccine manufacturers and the government.

Kaethe Douglass:

"The fact that Iowa's 700 percent increase in autism began in the 1990s, right after more and more vaccines were added to the children's vaccine schedules, is solid evidence alone," says state Sen. Ken Veenstra. But Veenstra is wrong. That isn't evidence. That isn't anything but coincidence. The 1990s also saw a sharp increase in the use of car seats for children, but no one is blaming them. A 700 percent increase in autism, or any other diagnosis, is much more likely to indicate a growing awareness of a possible diagnosis, rather than an actual increase in patients suffering particular symptoms. And if Veenstra cared to do a little bit of research, he would see that the less specific diagnosis of "mental retardation" dropped as sharply as autism increased.

A good point. I didn't know enough about the numbers to work it into my piece. It's also another nice example of how RFK Jr. confused correlation with causation.

Erin Amerman:

In the past five years, hundreds of studies have been done by independent researchers looking for a correlation between vaccines, thimerosal and neurologic disorders such as autism. The studies have repeatedly failed to find any such link. However, the media neglects to report this and instead latches on to one study performed in 2003 that did find a statistical correlation between thimerosal and autism. This is a grave disservice to the general population, because many fail to understand that the key in determining the validity of a research study is in repeatability of the results. The results of the 2003 study have never been repeated. Additionally, on closer examination, the 2003 study was found to have many design flaws, which call into question the validity of the results....

....The question that remains on the minds of many is that if thimerosal represented no health threat, why did the CDC and the FDA recommend its removal? Simply put, it was removed to appease the public. It is far easier to remove the preservative than it is to risk the health of thousands of children whose well-intentioned parents opt not to get them vaccinated. Why risk the health of these children, and indeed the health of the general population, when the preservative could easily be removed?

Quite correct! We're a rich country. We can afford to replace multiuse vials (the main reason for needing a preservative in vaccines in the first place) with single-use vials. So can Europe, Australia, and much of the rest of the developed world, and if removing the thimerosal in vaccines is necessary to keep parents from abandoning vaccination, regardless of whether the reason the thimerosal scares them is based on fearmongering and weak-to-nonexistent evidence, then I suppose we have to do it. Unfortunately, I don't know about Third World countries, though, where mass vaccination programs are most urgently needed and where there is the least money to pay for them.

These comments already in Salon.com lessened my sense of urgency in retooling my piece. Also, since my home is about to be invaded later this afternoon by an old friend, his wife, and their five kids, I probably won't have time to get to it until next week, if at all, given that I'm going to be on call for our group.

A couple of comments that I saw elsewhere took me to task for supposedly not proving my point that RFK Jr. had very selectively quoted the Simpsonwood transcript, pointing out that I had shown only one example. One reasons I picked only one example are that my piece was too long as it was. Also, part of the reason is that the damned transcript (warning: direct link to bigfile; don't click if you don't have time to let it download) is so long and because there is so little in the transcript that sounds conspiratorial, particularly in context. Try reading it yourself. I've only gotten through part of it, but I'll try to slog through the rest. It's very dull and dry. However, most of that's there is scientists debating the data and potential sources of bias and how to proceed from what was known in 2000. Read it yourself and decide if I was incorrect in my characterization--if you can stay awake while doing it.

One class of comments came from parents of autistic children. Not having an autistic child, there's no way I can truly understand what they're going through. I have a great deal of sympathy for the parents of any child with developmental disorders or other illnesses. Some of them believe chelation therapy helped their child. No matter how many times I repeat the fact that there is no evidence from clinical trials that chelation therapy does anything at all for autistic children and the fact that it is not without risks, it will never convince them. In any case, anecdotal evidence is only useful for formulating hypotheses to generate further research. I have dealt with the issue of alternative medicine testimonials before in relation to breast cancer. Some of what I said there is also applicable to autism and chelation therapy as well. I've also dealt with chelation therapy before in the context of its uselessness for treating cardiovascular disease. As happy as I am that the children of these parents are doing better, I still think it is a big mistake to credit chelation therapy for their improvement. For example, I can provide counterexamples for whom chelation therapy did no good. Finally, I realize what I've said may have sounded dismissive, but it wasn't. It is a natural desire to look for causes for illnesses like autism or for people to blame, and, even with my skepticism, I wouldn't bet the farm that I might not be tempted to take the same path if I were ever to have an autistic child. My take on this issue is here.

One comment that I feel I need to address directly came from Rob Helpy-Chalk:

Why does concern about a thirmisol/autism link automatically make one anti-vaccine and anti-science? Certainly we have seen other cases of drug companies surpressing evidence that one their products is harmful. Do you have to accept every aspect of current medical practice in order to avoid being labeled a quack or the victim of a quack?

I'm afraid you're using a bit of a strawman argument there, Rob. I never said that concern about a thimerosal/autism link makes one "anti-vaccine" or "antiscience." Berry picking data and bad science (even pseudoscience in some cases) to serve an activist agenda, as RFK Jr. did in his Salon.com article, is what makes one anti-science at least. I will concede that not all (or even most) who express concern about thimerosal are antivaccine, but enough of them are and the end effect of their activity is the same: making the parents of autistic children feel guilty for having vaccinated their children and instilling fear in parents about the safety of vaccines, all on the basis of exceedingly weak science. The data from Denmark and Canada are quite clear. Autism rates have not started to decline, despite no thimerosal in vaccines for 10 years. And, contrary to what one DU'er who really didn't like my post thinks, widening of the diagnostic criteria does not account for this lack of a decrease. (This same DU'er also clearly has no clue about the mortality rate of untreated meningitis and how fast these patients can die; although I will concede that RFK Jr.'s article was so sloppy that he didn't mention if these patients had bacterial or viral meningitis, which would have made a difference; using what I know of medicine in 1930, I made the educated guess that it was bacterial meningitis and that the scientists were trying to use thimerosal as an antibiotic.) If the connection between autism and mercury were as strong as advocates claim, the rates of autism in Canada and Denmark should have plummeted dramatically over the last decade regardless. They haven't there, and they probably won't in the U.S. over the coming decade, now that thimerosal has been removed from vaccines. Believe it or not, though, I'd be quite happy if they did, even if it proved me wrong and made me look like an utter fool for what I posted. Who wouldn't want autism rates to fall and find a signficant part of its pathogenesis?

Finally, thanks to Autism Diva, Kristjan Wager, Skeptico, HCN, Jim Laidler, Ali, Soapgun, and Kathleen Seidel for the tactical air support.

ADDENDUM: Two last updates on this issue are posted here and here.