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BLOG: September 2008
MMR shots and autism
"Study Dispels Link Between Autism and Measles Vaccine" and similar headlines are all over the Net. There is no reason anymore to doubt the safety of MMR (Mumps/Measles/Rubella) vaccine.
The proof? A group of researchers published results of a small CDC-sponsored (U.S. Centers for Disease Control) study, an attempt to replicate the 1998 study by Dr. Andrew Wakefield in which he found evidence of measles virus lurking in the intestines of children suffering from behavioral/developmental disorders. He hypothesized that it could be the virus who caused a new, peculiar form of inflamed, leaky gut that he named autistic enterocolitis, ultimately resulting in chain of reactions reaching the brain and affecting its function.
The new study found no significant measles virus presence in the group of 25 autistic children, nor in 13 control group children, all with gastro-intestinal problems, and all exposed to MMR from vaccination. The researchers concluded that it provides "strong evidence against association of autism with persistent MV RNA in the GI tract or MMR exposure" (Lack of Association between Measles Virus Vaccine and Autism with Enteropathy, Hornig, Briese, Buie, Bauman, Lauwers, et al., 2008).
Elusive evidence is not something quite new in this particular research, since Wakefield himself had difficulties in replicating his results. After several attempts he succeeded - or thought so. The CDC-sponsored study claims that their molecular measurement technology has better sensitivity. It may be so, but does it mean it is foolproof? Probably not. And the absence of the virus does not prove it wasn't part of the mechanism that triggered the disorder.
What makes this new study unique, is that it focuses on one of the centerpieces of Wakefield's hypothesis: that autism may be caused by the active measles virus in the intestinal tract. As study authors mention, over 20 studies after Wakefield's disturbing results, that found no relation between MMR and autism, did not look for the virus presence in the intestine. In other words, they were refuting Wakefild's results
without bothering to investigate the specific causative relationship he proposed as possible explanation.
The new study can claim that at least they were aiming at the target. What is interesting is that most of those other studies, refuting Wakefield's results, were objecting that his sample was too small (which is just about the size of this last study). Thus these other studies went on to examine statistical data, which is a highly unreliable basis considering all inadequacies of the reporting system.
Not that the new study is immune of similar objections. One important criterion in determining the probability of causative link between vaccination and autism was whether there is the evidence of gastro-intestinal (GI) problems that can reasonably be tied to MMR exposure (vaccination). In the study, in order to have MMR exposure tied to GI disturbance, GI disturbances with autism symptoms, or MMR vaccine to autism symptoms, the two had to have onset within the same month. Whatever "same month" actually may mean, it is just unrealistic to expect:
■ that the actual time-frame for development of chronic GI disturbance and/or autism symptoms will obey their "schedule", and
■ that the available data can be relied upon, considering - again - all inadequacies of the reporting system.
Nevertheless, the authors used this basis to obtain their numbers, and then go on to conclude that there is
difference between 12 of 25 cases
Neither study design nor interpretation of data are convincing.
And the history of CDC's involvement in this whole subject of MMR vaccine safety is less than spotless. In 2003, in connection to another reassuring study on MMR safety (published in the November issue of Pediatrics), a transcript of conversation at the CDC, obtained under the Freedom of Information Act, documented its officials admitting that MMR data can be manipulated to prove anything.
Apparently, there was more than just this statement involved, since the head of the CDC was rebuked for "selective use of data" by the U.S. representative Weldon.
Oh, by the way, the lead author of the study left the CDC two years prior study publication, to work for GlaxoSmithKline (one of the three manufacturers of the MMR vaccine).
The fact is, the CDC is, by its major role in the approval of the MMR vaccine and making it mandatory, far from being impartial in this controversy.
Even assuming that this new CDC-sponsored study is accurate, and that there is no measles virus presence in the intestinal tract of autistic children to speak of, it still doesn't prove the vaccine is safe. Wakefield's hypothesis may not be correct in its details. Afterall, he never claimed to understand specific mechanism by which the vaccine-might be causing leaky gut and its effect on the brain function. But independent research papers published in Japan, Norway, Ireland and the US - as well as this very CDC study -
support the link between autism and intestinal disease.
Lessening of autism symptoms in some 200 children at the Royal Free Hospital as their guts healed after Wakefield's instructions were implemented is also worth noticing.
It is possible that the virus creates environment in which immune system becomes aggravated, creating antibodies attacking self (the body). The presence of the virus is not required after that, it can be as well effectively terminated. The complexity of immune system actions certainly allows for such, and other possibilities, and so does wide range of individual sensitivities and responses.
In fact, Dr. Ian Lipkin of Columbia University - one of the study's authors - added, after stating that the study was a "rigorous analysis" and that they are "persuaded that there is no link between MMR and autism", that this
doesn't mean the
occasional child won't have an
He just wouldn't put a number on it.
Lipkin also pointed out that the study did not address any other vaccine or potential causes, including mercury or underlying disorders. This obviously includes other MMR vaccine ingredients which, according to the CDC Vaccine Ingredients PDF file, include bovine albumin or serum, chick embryo fibroblasts, human serum albumin and Neomycin.
These animal remnants, as well as remnants from aborted fetuses,
can cause adverse immune reaction even if not contaminated -
and the possibility of viral or other contamination cannot be excluded. The antibiotic Neomycin has known possible adverse effects which include nephro- and ototoxicity (kidney and inner ear damage, respectively), as well as neurotoxicity.
They - the officials, doctors and manufacturers - wouldn't put something into children's' vaccine if it can hurt them, would they. The answer is not a resounding "No!". They may not know it, and even when there are valid indications of vaccine ingredient being unsafe, they may not be exactly rushing to take the appropriate action.
Remember that Urabe strain of the mumps component of the MMR vaccine that was used for years, causing aseptic meningitis? Or thimerosal, mercury-containing vaccine preservative that's been just recently phased out from use in children's vaccines, but only under intense public pressure, after the media made the fact known.
This is not intended to scare anyone from vaccines. Merely to inform. To proclaim that the absence of measles virus activity in GI tract of autistic children - even if accurate - proves that the MMR vaccine is safe would be funny,
if it wouldn't be irresponsible.
There is a number of other possible factors that cannot be excluded nor ignored - one certainly being the uncertainty of individual response.
It is fairly obvious from historical records that the epidemic of autism begun unfolding before the MMR vaccine was introduced. That alone does not prove that the vaccine did not contribute to it. To find out what the facts are, we need to start out with straight talk - and that won't be easy. There is a lot at stake when it comes to the MMR vaccine - and immunization in general - and, for that reason, a lot of politics involved.
The risk of adverse effects from vaccination increases exponentially with the frequency of vaccination, and especially with multiple vaccines. One of possible trails back to the cause(s) of the Gulf war syndrome epidemics offered is the barrage of vaccines that soldiers underwent before their deployment. There was no official comment, but Britain's soldiers sent to Iraq and Afghanistan now receive their vaccines on an extended schedule.
The fact that as simple a move as making the MMR, a triple vaccine, safer for children by applying each one separately is so difficult to pass, speaks volumes about real priorities of the government and the manufacturers: money and self-preservation.