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Autism and vaccines: correlation is not causation

by Donald Prothero, Jan 22 2014

Just after the beginning of the year, leading anti-vaxxer and former Playboy Playmate Jenny McCarthy was in the news again. Several years ago, she apparently told Time magazine that her son Evan didn’t have autism, but (as doctors have long suspected) Landau-Kleffner syndrome. Then in January, McCarthy made several angry denials of this old interview. Frankly, I doubt that a source like Time magazine misquoted her—I think she’s lying again. She now claims that Time magazine inaccurately reported the facts! I think my irony meter just broke. Jenny McCarthy was a washed-up actress with nothing but a series of low-brow movies and TV shows to her credit until she became the national spokeswoman for the anti-vaxxer movement—a movement which was,  in a form of supreme irony, legendary for an inaccurate grasp of the facts, then shifting the goal posts on their demands when the mercury was removed from the vaccines and there was still no effect on rates of autism. She rejects mainstream science, yet cites biomedical science in support of her claim that her son really has autism. I think we should reject her claim outright, because she (like many anti-vaxxers) have no clue what mainstream science and medicine are about.

Now she and her anti-vaxx cohort are demanding that medicine and drug companies should “green the vaccine”! What the heck do they think the FDA is for? All vaccines must pass rigorous testing and quality control through the FDA, which has one of the most stringent standards for drugs and medicine in the world. Fat chance that she and her fellow science-denying protesters are going to help the process in any way! Meanwhile, she’s now on The View every day, giving an air of legitimacy to her form of pseudoscience. And the movement she bolstered is causing huge numbers of kids to go unvaccinated, get sick and sometimes die of preventable diseases—and, even worse, spread those diseases to and often kill infants too young for vaccination (even if their parents do believe in modern medicine). Continue reading…

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Legal Courts And Science

by Steven Novella, Jul 29 2013

Facebook is like a graveyard in a zombie movie, where old news items rise from the dead to have a second life. I am often asked about news items that are burning up Facebook, only to find that they are years old, but never-the-less they have to be addressed all over again. ]

One such item (actually a few items) is a 2012 news report about the Italian courts awarding money to the Bocca family a large reward because it concluded their 9-year-old son acquired autism from the MMR vaccine.

History here is a useful guide. The courts have historically often been out-of-step with the science, tending to err on the side of awarding compensation for possible harm. For example, until about the 1920s it was thought that physical trauma could cause cancer. Animal studies and epidemiological evidence, however, showed that there was no causal connection. Recall bias and increased surveillance were likely the cause of the apparent association.

Continue reading…

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Vaccine Denial Pseudoscience

by Steven Novella, Jun 03 2013

I was recently asked about this article, Bedrock of vaccination theory crumbles as science reveals antibodies not necessary to fight viruses, which is a year old, but is making the rounds recently on social media. I was asked if there is any validity to the article. It’s from NaturalNews (not to be confused with NatureNews), which means, in my experience, it is almost certainly complete nonsense.

For the average consumer my advice is to completely ignore NaturalNews and Mike Adams. He is, among other things, an anti-vaccine crank. This article is written by staff writer Ethan Huff.  Let’s take a close look  and see if it lives up to the site’s reputation.

He writes:

While the medical, pharmaceutical, and vaccine industries are busy pushing new vaccines for practically every condition under the sun, a new study published in the journal Immunity completely deconstructs the entire vaccination theory. It turns out that the body’s natural immune systems, comprised of both innate and adaptive components, work together to ward off disease without the need for antibody-producing vaccines.

Continue reading…

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Vaccine Acceptance Still an Issue

by Steven Novella, Dec 05 2011

Perhaps the weak link in the effectiveness of vaccines is public acceptance. Individual vaccine types vary in terms of their effectiveness, but all are reasonably effective and very safe. Vaccines are, in my opinion, one of the “home runs” of modern medicine – scientists hit upon a way to marshal our own immune systems to make us resistant or even completely immune to certain infectious diseases. The result has been a dramatic decrease in diseases that used to plague humanity, and the complete eradication of one (smallpox).

It is ironic that the greatest barrier to the effectiveness of the vaccine program is public acceptance. Part of the problem is that very high acceptance is needed in order to achieve what is called “herd immunity” – where there is sufficient protection in the population that an infected individual will likely not cause an outbreak.

In the US the numbers are pretty good, and have remained so even through the recent increase in the anti-vaccine movement. About 68% of children complete the full routine vaccination series. Many of the individual vaccines have compliance rates in the 90s (MMR, for example, was 92.1% in 2008). The level required for herd immunity varies, but it is generally around 85-90%.

Continue reading…

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by Steven Novella, Apr 25 2011

There is another major measles outbreak in Europe. The WHO reports:

The World Health Organization said Thursday that France had 4,937 reported cases of measles between January and March – compared with 5,090 cases during all of 2010. In all, more than 6,500 cases have been reported in 33 European nations.

That is four times the rate of 2010. I know – these reports are almost getting boring. The shock has worn off – we have come to accept that previously conquered diseases (at least reduced to minimal cases without outbreaks) have come back. The cause seems clear – outbreaks occur where herd immunity has been lost due to vaccine non-compliance. Fewer people are getting vaccinated, and not much fewer. But the numbers are falling below herd immunity levels in pockets. When vaccination rates fall below a certain level, then infectious organisms are able to spread and cause an outbreak.

The anti-vaccine movement has successfully spread unwarranted fear of vaccines, resulting in the compromise of herd immunity. There is a toll of morbidity and mortality associated with this movement.

Continue reading…

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The Long Awaited CDC Trial on Thimerosal and Autism

by Steven Novella, Sep 13 2010

We can add one more study to the pile of evidence showing no association between exposure to thimerosal (a mercury-based vaccine preservative) and autism. The article: Prenatal and Infant Exposure to Thimerosal From Vaccines and Immunoglobulins and Risk of Autism, is published in the latest issue of Pediatrics, and shows no association between prenatal and infant exposure to thimerosal and three forms of autism – autism, autism spectrum disorder, and regressive autism.

No one study can ever be definitive, but now we have a large body of evidence from multiple studies showing a lack of association between thimerosal and autism. This won't stop the dedicated anti-vaccinationists and mercury militia from continuing their anti-vaccine propaganda, but hopefully it will further reassure those who actually care about the science.


This has been a long and complex story, so let me review some of the background. Diagnosis rates of ASD have been climbing for the last 20 years, prompting some to search for an environmental cause. The existing anti-vaccine community, not surprisingly, blamed vaccines. This was given a tremendous boost by the now-discredited study by Andrew Wakefield concerning MMR (which never contained thimerosal) and autism. When the evidence was going against MMR as a cause, attention turned to thimerosal in some vaccines. This notion was popularized by journalist David Kirby in his book, Evidence of Harm.

Continue reading…

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Breaking News: The Government Wants to Poison Children!

by Brian Dunning, Jul 29 2010

I received this from a listener. She noted the following on the website “” (quite the ironically named website):

They Just Don’t Learn: CDC Votes To Poison Children Again With Two Doses of Vaccines

Parents of children over 6 months and under 9 years beware. The Centers for Disease Control (CDC) is once again choosing to adopt policies which poison your children with what is now two doses of seasonal flu vaccine this fall.

So she emailed the guy the following: Continue reading…

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The Anti-Vaccine Environmentalist

by Steven Novella, Apr 12 2010

The anti-vaccine movement, as is probably typical for ideological movements, has natural enemies and allies. Once the notion that mercury in the form of thimerosal in vaccines might be responsible for neurodevelopmental disorders (it’s not) become popular in the anti-vaccine crowd, this made them natural allies with the “mercury-militia” – those who blame environmental mercury for a host of ills. That fact that some anti-vaccinationists seek to provide their children on the autism spectrum with unconventional biological treatments, based on their disproved “toxin” hypothesis, made them natural allies with the alternative medicine community. Both seek freedom from pesky regulation, and rail against the perceived deficiencies of science-based medicine.

Another ideological alliance is brewing – that between the anti-vaccine movement and extreme environmentalists. This post is not a commentary on environmentalism, and please do not take it as such – the purposes and  claims of the two movements are quite distinct. But they share a common thread: distrust of scientific experts and government regulators who reassure the public that environmental exposures are safe.

Robert F. Kennedy Jr. has been the most prominent environmentalist to take up the anti-vaccine cause, in several articles and speeches. While he appears to be only a part-time anti-vaccinationist, his celebrity and street cred among evnironmentalists led a great deal of weight to his paranoid musings about scientific fraud and government coverups. It seems he wants to recapitulate the moral clarity that his uncles displayed in the 1960s, defending the little guy against abuses by the powerful and privileged. He is ready to see a conspiracy, and he wants to be the crusader for environmental justice – and if kids are the alleged victims, all the better. His article in the Huffington Post – “Attack on Mothers,” says it all.

Continue reading…

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Another Libel Suit – This Time Against Paul Offit

by Steven Novella, Jan 04 2010

We are still in the midst of the libel suit brought by the British Chiropractic Association against Simon Singh, and now another defender of science has been targeted by such a suit. Paul Offit, Amy Wallace, and Wired Magazine have been sued for libel by Barbara Loe Fisher, the head of the National Vaccine Information Center (NVIC).

Here is a pdf of the complaint.

The subject of the suit is the excellent article by Amy Wallace criticizing the anti-vaccine movement. Wallace was attacked for this piece by anti-vaccinationists – essentially because she got the story correct. Wallace pointed out that the science strongly favors vaccine effectiveness and safety, and that the anti-vaccine movement is dangerously wrong – hurting the public health with their misinformation. The anti-vaccinationists were apparently very upset over be called out by a mainstream journalist. They got a lot of bad press this year, the Chicago Tribune also did a series of articles detailing the dangerous pseudoscience of the anti-vaccine movement. Wallace’s article earned her a place in the infamous baby-eating photo (along side Offit and yours truly) that only served to further embarrass the anti-vaccine movement via the blog, Age of Autism.

The law suit, in this context, seems like just the next step in the campaign against Offit and Wallace.

Continue reading…

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Bill Maher Followup

by Steven Novella, Oct 12 2009

If you peruse skeptical blogs you are probably familiar with the recent controversy over giving the Richard Dawkins award to Bill Maher by the Atheist Alliance International (AAI). To summarize, the AAI decided to recognize Bill Maher with their award named after Dr. Dawkins. The award is for:

The Richard Dawkins Award will be given every year to honor an outstanding atheist whose contributions raise public awareness of the nontheist life stance; who through writings, media, the arts, film, and/or the stage advocates increased scientific knowledge; who through work or by example teaches acceptance of the nontheist philosophy; and whose public posture mirrors the uncompromising nontheist life stance of Dr. Richard Dawkins.

The part that caused controversy was the bit about “advocates increased scientific knowledge.” A number of skeptics (Orac, I think, was most verbose)  had a problem with this because Bill Maher is an advocate for medical pseudoscience. He does not believe in vaccines, he denigrates “western medicine” as a scam, and he has a problem with germ theory.

Continue reading…

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