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Vaccines don't cause autism, in case you had residual doubts
Researchers from the [California] State Public Health Department found that the autism rate in children rose continuously in the study period from 1995 to 2007. The preservative, thimerosal, has not been used in childhood vaccines since 2001, except for some flu shots. Doctors said that the latest study added to the evidence against a link between thimerosal exposure and the risk of autism and that it should reassure parents that vaccinations do not cause autism. If there was a risk, the doctors said, autism rates should have dropped from 2004 to 2007.
Here is the full story. Here are many other summaries.
Addendum: Kevin Drum and commentators add more.
Posted by Tyler Cowen on January 8, 2008 at 03:48 PM in Science | Permalink
Comments
The FDA mandated that manufacturing of thimerosal-containing vaccines be stopped as of October 2002. There was an existing 2 year supply of these vaccines, which ment that the first non-thimerosal vaccines started to be used in mid to late 2004. Kids get vaccinated from birth to about 18 months old. This means that the first group of kids receiving vaccines thimerosal-free would have completed receiving them in late 2005 or early 2006.
Autism is usually diagnosed in kids when they enter grade school at the age of 6. Since the first generation of kids to receive thimerosal-free vaccines will enter first grade in 2010. So, if the theory that thimerosal causes autism is correct, the rate of autism diagnosis will not start to decrease until 2010-2011.
The journalists writing these articles either know this and are deliberately ignoring this, or they are too lazy to do any amount of fact-checking.
Since fact-checking is considered an integral part of a journalist's job, either case means that the journalists writing these articles are willfully negligent.
Posted by: kurt9 at Jan 8, 2008 5:37:43 PM
Kurt9, every account I can find states that *for California* the thimerosal stopped in 2001. Now that may be wrong, but I don't think these articles have the simple error that you are claiming.
Posted by: Tyler Cowen at Jan 8, 2008 5:53:34 PM
Kurt9's dates are all wrong. Manufacturers, at the government's urging, started phasing out thimerosal in 1999, and the first non-thimerosal vaccines were already being manufactured by then. By the end of 2001, there were few thimerosal vaccines still on the market, with the exception of inactivated flu. Also, the diagnoses of autism that are studied in the California report begin at age 3, and those diagnoses have risen monotonically in the last twelve years, even though thimerosal has been phased out.
Vaccination doesn't cause autism. Period.
Posted by: K. Williams at Jan 8, 2008 6:35:37 PM
Autism may or may not be linked to thimerisol. But from accounts of mothers, scientifically verified or not, there is a strong correlation between vaccination and autism. Take a look at the recommended schedule and ask yourself if a tiny baby could reasonably withstand that kind of assault on his immune system (well intentioned or not).
Posted by: anne at Jan 8, 2008 8:54:12 PM
We have two babies who have had to be vaccinated, even though it scares the hell out of us. In Australia they can refuse child-care if your child hasn't been vaccinated, and may even refuse the child at school.
I don't know if there is any relation between the MMR vaccine and Autism, but I hope they find out asap. I wonder what the results have been in Japan, who banned the MMR years before anyone else.
Posted by: Gary Storm at Jan 8, 2008 9:12:44 PM
"Take a look at the recommended schedule and ask yourself if a tiny baby could reasonably withstand that kind of assault on his immune system (well intentioned or not)."
Reads like sound science to me, I am sold anne. Why listen to PHDs and MDs when I have your reason to guide me.
Posted by: DJB at Jan 8, 2008 9:14:10 PM
K. Williams,
I stand by my comments. The FDA first approved thimerosal-free vaccines in 1999. The industry transition to the manufacture of thimerosal-free vaccines would have taken 2 years or so (during this time, there is over lap production of both thimerosal and thimerosal-free vaccines), which puts us into mid to late 2001.
The shelf life of thimerosal vaccines is 2.5 years. Since the thimerosal vaccines are easier and cheaper to store (do not require refrigeration, longer shelf-life), MDs stocked up on this (they do this). So, the stocks of the thimerosal-containing vaccines would not have run out until 2004. Since kids are vaccinated from birth to 18 months old, the first generation of kids vaccinated with the thimerosal-free vaccines would have been done in 2005. These kids would turn 3 years old in 2008.
So, the earliest diagnosis done on "thimerosal-free" kids could be done in 2008, at earliest.
The kids that get diagnosed at 3 years old are those who have parents who happen to be "on the ball" about these sorts of things. Most kids who are autistic do not get diagnosed until age 5 when they enter kindergarten. In which case, the drop in autism will not be noticed until 2010.
In short, I stand by my point.
Tyler,
You have an over-appreciation of the journalism profession. Journalists publish these kinds of articles all of the time because they do not want to jeopardize their "access" to the important people they like to hang with.
My friends who worked with NASA in the 80's had a clear experience with this when the Challenger blew-up in 1986. The Journalists who covered NASA knew full well that there were problems with the SRB (solid rocket boosters), but never published anything about this because they did not want to loose their access to the key NASA people. When the Challenger blew-up, many of these journalists ended up with egg on their face and still ended up loosing access to the key NASA people.
Also, I notice many inaccuracies in journalism. When the chechnyan terrorists held up that school in Russia a few years ago, I saw the news coverage on it. The reporter said that the troops in helmets that were dealing with it were "local police" when their helmets were clearly labeled "Speztnaz" in Russian (you could actually see this on the screen). I told a friend of mine about this and he told me that this kind of sloppiness is very common in journalism.
Also, don't forget the forged "National guard" documents about Bush that Dan Rather reported on shortly before the 2004 election.
Posted by: kurt9 at Jan 8, 2008 10:51:22 PM
"Take a look at the recommended schedule and ask yourself if a tiny baby could reasonably withstand that kind of assault on his immune system (well intentioned or not)."
After you do that, take a look up at the sun as it rises and sets every day and ask yourself if it's reasonable that it doesn't rotate around the earth.
Posted by: Matt at Jan 8, 2008 11:17:26 PM
Neither this blog nor Drum's points to my favorite theory for the increase in autism, Simon Baron-Cohen's theory that it's (partly) due to assortative mating, like marrying like.
Engineers and other people with systematic minds (i.e., nerds) are much more likely to have autistic children than non-engineers. Nowadays engineers are finding and marrying other engineers in places like Silicon Valley, and in those places, the rates of autism are skyrocketing.
Posted by: Cardinal Fang at Jan 8, 2008 11:50:47 PM
What is this idea that vaccines "assault" the immune system? They take one piece of protein (known as an epitope), and get the immune system to create antibodies to it. Real bacteria and viruses have dozens of epitopes, so how could a vaccine be overwhelming?
Posted by: Carlos at Jan 9, 2008 12:20:12 AM
Relevant paper here: http://pediatrics.aappublications.org/cgi/content/full/109/1/124
Posted by: Carlos at Jan 9, 2008 12:21:48 AM
I hate to be another guy on the Internet talking vaguely about a study, but I don't have time to look it up. I distinctly remember a study of European countries which phased out thimerosal long ago and none showed any change in Autism rates.
The only possibility of thimerosal having any effect at all is if some other factor, such as better reporting, has outweighed these countries or states doing away with the preservative. However, if it really was as big a deal as people claim, the R squared value would have to overwhelm such secondary causes as like mating and better reporting.
Posted by: Matt Waters at Jan 9, 2008 12:40:23 AM
"In Denmark, thimerosal has not been used in vaccines for children since 1992."
Posted by: at Jan 9, 2008 1:34:54 AM
"But from accounts of mothers, scientifically verified or not, there is a strong correlation between vaccination and autism."
Why am I not surprised that Anne - the intellectual giant of the leftist commentators on this blog - doesn't understand basic scientific principles and the problems they are intended to protect studies against?
Posted by: Erik at Jan 9, 2008 1:46:51 AM
The timing of MMR vaccinations and the timing of when symptoms of autism are apparent just happen to coincide. Human brains just don't get the "correlation is not causation" paradigm. Careful studies of autism, have I believe, tended to indicate its cause lies very early in development, well before any vaccinations. There have been several articles on it in Scientific American.
Posted by: reason at Jan 9, 2008 5:42:30 AM
Japan didn't ban the MMR. It banned the use of mercury in the MMR in the 90s. Experience is exactly the same as Denmark's above. No change in autism incidence.
Re. Baron Cohen. There's a few papers here.
http://www.eqsq.com/resources.php
(Scroll down to research papers).
His theory is based on the idea that there is a spectrum of brain types, from empathising (what we might stereotypically call "female") through to systemising (ditto "male") and that while there is a higher probability that a woman has the empathising brain type, some 17% have the systemising (and vice versa of men and empathising).
Autism is, in his view, an extreme form of the systemising brain type and thus the rise in assortative mating explains the rise in autism. As we all now (in massive contrast to times even a few decades ago) choose our mates from our college or work, rather than from the extended family's friends and social life, more systemisers are marrying systemisers and thus increasing the number of such.
That's only a thumbnail of the theory, of course.
If anyone's up for it, you can see where you are on the spectrum by taking these tests.
http://www.eqsq.com/eqsqtest.php
Note that where you are is defined by the ratio between the two results, not the actual numbers themselves.
Posted by: Tim Worstall at Jan 9, 2008 7:57:01 AM
Kurt9:
Do you have any evidence that manufacturers produced so much excess vaccines with thimerosal and that the thimerosal-free vaccines weren't given to kids until 2.5 years later? Just because it is theoretically possible that kids could have received thimerosal vaccines until 2004 doesn't mean that the vast majority of kids did so. This would have to happen for autism rates to continue rising due to thimerosal. Given physicians fears of lawsuits, I anticipate that most gave the thimerosal-free versions of the vaccines where possible. Thus, I believe the news story. Also, if thimerosal-free vaccines are so difficult to store, then under your scenario of a 2+ year supply of thimerosal-based vaccines, there would have been very few sales of thimerosal-free vaccines. So, if you can demonstrate this fact, or if you can demonstrate that the vast majority of vaccines given to kids through 2004 had thimerosal, then I would likely accept your position.
Posted by: Craig at Jan 9, 2008 8:19:04 AM
My family doctor is a long life friend, being both of us in our sixties.
He is a serious man, with a lot of experience and nothing of new age mumbo-jumbo in his head.
None of his three grandsons have been vaccined from a single thing.
His opinion is that where we live (Barcelona-Spain) the risk of contagion for the diseases that are usually prevented by vaccines is sow low that the negative effects on the body of more than 20 vaccines in the first 2 years of live are more to fear.
He has never mentioned autism, of course.
Posted by: claudio at Jan 9, 2008 8:32:47 AM
Does your sober doctor friend think that contagion becomes less likely because everyone is vaccinated?
Posted by: Barbar at Jan 9, 2008 9:21:21 AM
Engineers and other people with systematic minds (i.e., nerds) are much more likely to have autistic children than non-engineers. Nowadays engineers are finding and marrying other engineers in places like Silicon Valley, and in those places, the rates of autism are skyrocketing.
Hmmm, maybe that silly TV show "Beauty and the Geek" isn't quite so silly after all. It might actually be onto something.
But seriously ... if this assortative mating theory is correct, the increase in autism should be self-limiting for the simple reason that relatively few male nerds (e.g. Silicon Valley engineer types) marry and have children. Complaining about how women reject nerds in favor of Alphas is of course a very popular Internet meme, but that sort of rejection might serve valid evolutionary purposes.
Posted by: Peter at Jan 9, 2008 9:33:35 AM
Research studies have long confirmed that there is no link between vaccines and autism. What we usually are down to is "belief" - "I don't believe that".
This is just another case where unsubstantiated fear and misinformation increase risk. Food irradiation is another. We know that e-coli makes people sick (& even causes death), and that food inspection cannot possibly prevent the problem. A technology exists that does not alter the food in any way and is completely safe that is not used because people are afraid of the word "irradiation". 40 years should be enough time for any safety technology to prove itself.
Rather than just believing every scary thing you read, try downloading the original research studies. Look for long term studies with large samplings. When you read a book or article, look for bias. Try to read several pieces about the subject to get different opinions. Don't just pick the articles that substantiate your own opinion but try to keep an open mind. It is very human to access the message based upon one's trust of the source. As they say in I, Claudius "Trust no one" - scrutinize the message and see if it can stand on its own merits.
There are also many scary emails with misinformation that people believe. Lead in lipstick & dioxin in saran wrap are 2 of the common ones. Websites like www.mythbusters.com help consumers to sort between the fact and fiction. Next time you get a warning email, check it before you buy it.
Bottom line: If you want to know something, don't just take someone's word for it. While asking someone is the fastest way to learn something, it is also the easiest way to get the wrong answer. None of us is infallible.
Posted by: Sophie at Jan 9, 2008 9:34:29 AM
"relatively few male nerds (e.g. Silicon Valley engineer types) marry and have children. "
I don't know why you'd say that. It's not true at all, at least in Silicon Valley. Silicon Valley nerds get married and have children. I'm a Silicon Valley nerd married to a nerd, with a nerd-child. Most of my friends are nerds who are married to other nerds and have nerdy kids.
Posted by: Cardinal Fang at Jan 9, 2008 3:25:35 PM
A little thinking quickly shows that the assortive mating explanation for the rise of autism is fraudulent. In the early 70's, the rate of autism was 1 in 20,000. Today, the rate is 1 in 166. The rate of autism has increased by more than 100 times in the past 30 years. If assortive mating was the cause in the increase in autism, it is likely that the rate of autism might increase 40-50% over the same 30 year period.
It is simply insane to believe that genetic factors could cause a 100 times increase in the incidence of a disease. Human genetics simply does not change that much in a 30 year period.
It is obvious that the increase in autism must be environmentally caused. There are two plausible environmental causes. One is that a new industrial compound (pollutant) has appeared and become prevalent in the environment in the past 30 years. Perhaps the compounds used in semiconductor processing are getting out of the fabs and are causing autism. The other plausible environmental explanation is that autism is caused by something that MDs do to kids, most likely vaccines.
There are no other plausible explanations for the rise in autism. Genetic explanations clearly cannot be responsible and the magnitude of the increase makes it clear that genetic explanations are fraudulent.
The fact that the medical industry conducts no research into the possibility that it is a new industrial pollutant causing the increase in autism makes it clear that they know full well that this is not the cause.
Craig,
Vaccines containing thimerosal are easier to store and have a longer shelf-life. They are also cheaper. So, MDs would of course stck up on them knowing full well that they are about to become unavailable in the near future. The manufacturers, responding to this demand will ramp up oroduction, especially since they are facing retooling costs to convert over to the manufacture of the thimerosal-free vaccines.
Also, the MMR vaccine can only be made with thimerosal. Thimerosal-free versions of these three vaccines can only be made as separate vaccines.
I will have more about Europe and Japan later.
Posted by: kurt at Jan 9, 2008 3:52:30 PM
http://www.cbc.ca/health/story/2006/04/03/autism-children-rate-20060403.html
There is another explanation for the rise in autism: misdiagnosis.
The majority of cases of autism and ADD are now being diagnosed by teachers rather than psychiatrists. Many healthcare professionals report being pressured by schools to confirm the diagnosis according to an article published a year ago in the Wall St. Journal.
Posted by: Sophie at Jan 9, 2008 5:01:26 PM
I'm surprised by how few references to incentives there are in the comments. Where do the incentives lie in studies of the risks of thimerosal exposure? There is a strong incentive to find no link because a documented link would open the flood gates of lawsuits against the drug companies. Researchers must know their futures would be much brighter if they come out on the side of the drug companies. The incentive to finding there is a link is much weaker: the vaccinations with thimerosal are no longer given, so there is no urgency in finding whether a link exists. Of course, if the rise in autism is not due to thimerosal exposure, then researchers have to find another explanation, but that research would continue even if it were found there is a link between thimerosal exposure and autism.
Posted by: Al at Jan 9, 2008 5:15:42 PM
