A new study published yesterday (Monday) in the journal Pediatrics provides more evidence against any link between thimerosal (a mercury-based preservative in some vaccines) and autism or other neurological disorders. This study adds to the large and growing body of scientific evidence for the safety of vaccines, and contradicting the claims of the anti-vaccine movement that vaccines cause autism.

The study is a bit fortuitous in that it was not originally designed to probe this question. Rather, this was a safety and efficacy study of the acellular pertussis vaccine conducted in Italy between 1992 and 1993. But it created a cohort of children who were carefully screened and monitored, and randomized to different exposures to thimerosal. This allowed the researchers to go back 10 years later to survey and examine the children for neurological disorders.

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Recently there has come to attention a potential cluster of autism cases among Somali immigrant in Minnesota and Sweden. If true, this could potentially be an important clue as to the pathophysiology of some types of autism.

Autism is unknown in Somalia, but the children of Somali immigrants in two communities in Minnesota and Sweden have reported higher numbers of cases than the general population. This suggests that there is an environment trigger – something they are getting or not getting in their new communities that is different than Somalia. This report indicates:

In Minneapolis, Somalis account for 6 percent of the city’s public school population, but make up 17 percent of early childhood special education students who have been labeled autistic, according to data aggregated by the Minneapolis Public Schools.

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A new study published in PLOS One shows no association between the MMR vaccine and autism or the presence of measles virus in the gut of children with autism and GI symptoms. This is yet more evidence against the claim that the MMR vaccine is responsible for some autism cases. Of course, no one study can clearly settle a complex medical question. The entire literature must be taken as a whole, and when we do this it becomes clear that the evidence is strongly against any association between MMR and autism. This new study is an important addition, and strengthens this conclusion.

This study has some interesting features. The lead author is Mady Hornig – who (until this study) was one of the research darlings of the anti-vaccine crowd. It will be difficult for the anti-vaccinationists to dismiss this study as coming from a vested interest or someone with an agenda, as they have previously be extolling the virtues of this particular researcher. Further, in the press release we learn:

(John Snow Professor of Epidemiology and director of the Mailman School’s Center for Infection and Immunity) adds, “The study design process was a critical piece for us, as there is still so much public concern over the safety of the MMR vaccine. For this reason, we involved the autism parent/advocacy community as we designed the study to ensure that all issues were being addressed. We are hopeful that this process of community engagement will build important partnerships among members of the autism community, physicians, public health agencies, and clinical researchers; serve as a paradigm for the conduct of future studies to understand the causes of this disorder; and facilitate the rapid communication of clinically relevant scientific findings to the broader community.”

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In response to my blog post on Monday, David Kirby wrote a response in the Huffington Post and Dr. Jon Poling (father of Hannah Poling) wrote an open letter to me, placed in the comment section and posted at Age of Autism. It seems only polite that I respond to their kind attention.

The primary focus of my original post (which I further developed yesterday) was that the media is focusing too much attention on what celebrities and politicians are saying about the controversy surrounding the discredited notion that vaccines are a significant cause of autism. Over the past year Jenny McCarthy (now joined by her boyfriend Jim Carrey) has become the major spokesperson for a movement that, at its core, is anti-vaccine and is dedicated to the scientific opinion that vaccines are toxic and cause autism. Recently actress Amanda Peet joined the fray, professing her belief that vaccines are safe, are not associated with autism, and that parents who do not vaccinate their children are “parasites” for depending on other parents who do. (She later apologized for that remark, calling it “divisive”.)

While I appreciate Amanda Peet’s support, I feel strongly that scientific questions should be handled by the scientific community. Celebrities are great when they support causes – but when they second guess the scientific community and decide to advocate for their own scientific conclusions, they are more likely to cause harm than good. Continue Reading »

Yesterday I wrote about the fact that Amanda Peet had come out in support of vaccine safety, adding her voice to those who wish to counter the now discredited notion that vaccines are linked to autism. While I admire her for essentially reading the situation correctly, I lamented the fact that celebrities (like Jenny McCarthy) are getting too much attention for their opinions on scientific questions. Today, while bouncing around the blogosphere, I see that McCarthy and Peet were only the tip of the iceberg.

Britney Spears

Orac reported yesterday that Jenny McCarthy held a fundraiser for her antivaccination group (mischaracterized as an autism charity) Generation Rescue. Her boyfriend, Jim Carrey, was there, of course. But also making an appearance was Britney Spears. Orac nailed it when he wrote: “Because no one knows parenting and science like Britney Spears, I guess.”

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Much of the controversy surrounding autism in recent years is based upon the premise that there is an autism epidemic – that autism rates are climbing. However, the evidence strongly suggests that this is not the case and that autism diagnoses are increasing through a combination of broadened diagnosis and increased surveillance and awareness. However, proponents of various discredited theories, such as those anti-vaccinationists who claim there is a link between vaccines and autism (there isn’t) want to believe there is a true epidemic because that in turn implies an environment factor (like the vaccines they despise).

But the environmental hypothesis of autism, while impossible to completely eliminate, has not been fairing well. On the other hand, the theory that autism is largely (if not entirely) genetic has been very fruitful. Researchers are finding more and more genes that correlate strongly with autism. Also, studies have shown that the risk of autism rises with paternal age – suggesting that aging sperm may play a role. It is also true that as our ability to diagnoses autism more reliably, and based upon earlier and more subtle signs, we are finding that infants show early signs of autism – before they receive most of their vaccines or environment has much of a chance to play a role.

Essentially, multiple independent lines of evidence are converging on the conclusion that autism is dominantly genetic. Well, now there is yet another line of evidence supporting this conclusion

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Dr. Offit is an infectious disease and vaccine specialist who has been extremely active in defending the science of vaccine safety and effectiveness against ideological attack from antivaccinationists. He has recently published an excellent article in the New England Journal of Medicine in which he reviews the Hannah Poling case – the case of the girl with a mitochondrial disorder who developed encephalopathy following a series of vaccines. He makes many very good points and the entire article is worth reading.

I wrote previously about the Hannah Poling case. This remains a vexing case because it in no way supports the claim that there is a link between vaccines and autism, but it is a complex case and is easily presented by antivaccine activists as if it does support a link. Dr. Offit echoes my position that the details of the case, when put into proper perspective, do not support claims for such a link.

Anti-vaccinationists who claim, against the prevailing scientific evidence, that there is a link between autism and vaccines, have been busy recently spamming science bloggers (at least those who have posted on this issue before) with new evidence they believe supports a connection. The evidence is a small study involving giving vaccines to macaques and measuring various neurological outcomes. Here’s mine – Kim Spencer left this comment on my recent post about the chelation related death case:

when are you going to get down and dirty on the new monkey study? waiting on your opinion on how this could be wrong… http://www.ageofautism.com/2008/05/pediatric-vacci.html

can’t wait for your explanations!!!

Notice the implication that I have been somehow avoiding taking on this new study. I am sorry to keep you waiting so long, Kim, given that this study was presented as a series of three abstracts at the latest International Meeting for Autism Research. You will note that they are dated May 16th 2008 – this is my very next blog post.

This also bears directly on my first criticism of this evidence – abstracts presented at such meetings do not pass the same rigorous peer-review as full papers published in respected journals. Most abstracts never see the peer-reviewed light of day. Continue Reading »

A new study published in the current issue of Pediatrics looks at the association between mainstream media coverage of the claim that there is a possible correlation between the mumps measles rubella vaccine (MMR) and autism and the rate at which American parents refused the MMR vaccine for their children. The results were a bit surprising.

Smith et. al. used the LexisNexis database to track media reports of Wakefield’s initial study showing a possible connection between MMR and vaccines (the study was later discredited, and to date there is no evidence to support such a connection). They compared this to data reporting the incidence of parents refusing just the MMR component of the routine childhood vaccine schedule (so-called selective MMR nonreceipt). Their hypothesis was that media coverage would correlate with an increased incidence of selectively refusing the MMR. But that is not what they found.

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No. But David Kirby and other anti-vaccinationist ideologues and members of the so-called mercury militia would like you to think so. For background, the Autism Omnibus refers to a set of hearings before the Vaccine Injury Compensation Program regarding claims by about 5000 parents that their childrens’ autism was caused by vaccines. These claims are primarily based upon the various hypotheses that the MMR vaccine, or thimerosal in some vaccines (but not MMR), or the combination of both, is a cause of autism.

So far there have been hearings, but only one final decision. In November the US government settled one case in favor of the petitioner. This is the case those who have supported the failed hypothesis that vaccines cause autism now point to as admission that they were right all along (or at least as a means of stoking the flames of fear about vaccines.) But the US government did not admit vaccines cause autism – they conceded one case that is highly complex and not necessarily representative of any other case and cannot be reasonably used to support the vaccine/autism connection.

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