Archive for September, 2008

The end of a 10 year old fallacy about measles vaccine

Thursday, September 18th, 2008

I certainly forgive you if you missed the story last week that measles vaccine does not (DOES NOT!) cause autism. There were no celebrities touting the results. No Larry King specials. Just a small piece in the back pages of the bigger newspapers. Yet, this was a really big story for everyone who has been laboring for a decade to undo the harm caused by a poorly done British study.

     The initial concerns regarding a possible link between MMR and autism (see Chapter 7, Germ Proof Your Kids – The Complete Guide to Protecting (without Overprotecting) Your Family from Infections ASM Press, Washington, D.C. 2008) were generated by a report in 1998 of 12 children in England who developed autism within a few weeks of receiving the MMR; these children also had intestinal symptoms. The investigators hypothesized that the measles virus in the live, but weakened MMR vaccine damaged the intestines, allowing toxins to escape from the intestines into the blood, reach the brain, and cause the developmental problems of autism. A subsequent study by the same investigators identified evidence of measles virus in more intestinal biopsies taken from kids with autism than from kids without autism. These published reports generated enormous media attention, and an instant, and persistent, controversy was born.  As with most controversies, new perspectives emerged with time and data were more critically assessed. Many other experts reviewing those two initial studies identified numerous and serious flaws with the way in which those investigations were conducted and with the interpretation of the results.  

In addition to finding flaws with the original studies and results, many lines of evidence have since accumulated to refute the association between measles vaccine and autism. These include a study from Denmark of more than 500,000 kids comparing those who did, with those who did not, receive MMR vaccine – the occurrence rate of autism in the two groups of kids was identical regardless of vaccine status. Other studies have looked at large numbers of “home movies” made of kids prior to their diagnosis of autism and prior to their MMR vaccine, as well as home movies of other kids matched for age and other factors who didn’t ultimately get diagnosed with autism. Expert autism investigators who didn’t know whether the kids they were watching on the home movies went on to be identified as autistic or not were able to very accurately predict by the kids’ behaviors on the movies which kids would, and which would not be diagnosed with autism – and all of those telltale behaviors occurred before MMR was given to any of the kids. Thus, if a child received the MMR vaccine a month after the home movie was taken, and was diagnosed with autism two months after the home movie, there might be concern that the vaccine had something to do with the development of autism  – but the movies prove that the signs of autism in those kids preceded the vaccine and preceded the actual time of diagnosis of the disorder. Finally, studies of identical twins and of toxic exposures that occur during pregnancy that are known to cause autism all suggest that autism is a condition that develops prior to birth and is subsequently diagnosed when kids’ behaviors are more easily assessed – often around the time that vaccines are coincidentally given.  All of that evidence prompted the National Academy of Science’s Institute of Medicine (http://www.iom.edu/?ID=4705) and the American Academy of Pediatrics to conclude that the vaccine does not cause autism or autism spectrum disorder.

And then, there was last week’s non-headline – investigators repeated the exact experiments that were done 10 years ago, and found absolutely no evidence for the virus in kids with autism. None.

End of story – measles vaccine doesn’t cause autism. Well, not quite the end of the story. The study done 10 years ago resulted in a dramatic drop in the number of measles vaccinations that have been given because parents have been frightened. Fewer immunizations mean more cases of natural measles, and 2008 marks the highest number of cases of naturally-occurring measles in the U.S. since 1996. There is no scientific controversy about the dangers of measles – it can be a deadly infection.

Immunize your kids.