New Study Confirms that Mercury-Based Vaccines Don’t Hurt Children and are Safe

A new study from Italy adds to a mountain of evidence that a mercury-based preservative, thimerosal, once used in most vaccines doesn’t hurt children, offering much, much more reassurance to parents.

More Information:

Fox News is carrying an AP report that in the early 1990s, thousands of healthy Italian babies began to participate in a study of whooping cough vaccines. The infants received vaccines with one of two different amounts of the mercury preservative, thimerosal, in ALL of their routine shots.

Ten years later, 1,403 of those children took a battery of brain function tests. Researchers found small differences in only two of 24 measurements and those “might be attributable to chance,” they wrote in the February issue of the journal Pediatrics, which was released Monday.

Only one case of autism was found, and that was in the group that got the lower level of thimerosal.

Autism is a complex disorder featuring repetitive behaviors and poor social interaction and communication skills. Scientists generally believe genetics and/or environmental factors most likely play a role in causing the disorder; a theory that thimerosal is to blame has been repeatedly discounted in scores of large and well validated scientific studies.

“Put together with the evidence of all the other studies, this tells us there is no reason to worry about the effect of thimerosal in vaccines,” said the new study’s lead author, Dr. Alberto Tozzi of Bambino Gesu Hospital in Rome.

The debate over thimerosal and autism has been much stronger in the United States than in Italy, Tozzi said. But the researchers recognized a chance to examine the issue by going back to the children who had taken part in the 1990s whooping cough research.

Randomization sets the new study apart from all the others that have come before it. The random assignment of children rules out the chance that factors other than thimerosal, such as education or poverty, caused the results.

Thimerosal, used in some vaccines to prevent the growth of bacteria and fungus, hasn’t been in the vast majority of U.S. childhood vaccines since 2001, except for certain flu shots. Italy and other European nations began removing it in 1999. U.S. health officials recommended the removal of thimerosal as a precaution and to reduce the overall exposure of children to mercury.

Safety regulations still require multi-dose vials of vaccines to contain some type of preservative to prevent the spread of infection from contaminated vials.

The study, funded by the U.S. Centers for Disease Control and Prevention, drew praise from scores of outside experts.

“It’s yet another well done, peer-reviewed research study that has demonstrated there is no risk of any neurodevelopmental outcomes associated with thimerosal in vaccines,” epidemiologist Jennifer Pinto-Martin of the University of Pennsylvania told the AP.

“This becomes the fourth study to look for subtle signs of mercury toxicity and show the answer was ‘no,'” said Dr. Paul Offit, chief of infectious diseases at the Children’s Hospital of Philadelphia, the author of a book on autism research and the co-inventor of a rotavirus vaccine.

Tozzi said comparing children with no exposure to thimerosal could have improved the study. “However, if thimerosal were a cause of harm, it is likely that this effect would increase with the administered dose,” he said.

The children received either 62.5 micrograms or 137.5 micrograms of ethyl mercury from all their shots during their first year of life. Thimerosal breaks down as ethyl mercury in the body. Before the reduction of thimerosal in the United States, the maximum exposure for infants was 187.5 micrograms of ethyl mercury.

The researchers found the children in both groups scored, on average, in the normal range on 11 tests of memory, attention, motor skills and other brain functions.

Those 11 tests included 24 measured outcomes. Small, but statistical differences were found for only two of those areas, and only for girls. The girls with higher exposure scored worse on a finger-tapping test with their dominant hands, and on a vocabulary test in which they were asked to name common objects.

There was no difference in boys on those outcomes or others. Researchers also found no difference in tic disorders. And the one autism case found in the lower-intake group was likely a chance finding, Tozzi told AP.

The researchers describe their RESULTS this way, “Nearly 70% of the invited subjects participated in the neuropsychological assessment (N = 1403). Among the 24 neuropsychological outcomes that were evaluated, only 2 were significantly associated with thimerosal exposure. Girls with higher thimerosal intake had lower mean scores in the finger-tapping test with the dominant hand and in the Boston Naming Test.”

Their CONCLUSIONS are as follows: “Given the large number of statistical comparisons performed, the few associations found between thimerosal exposure and neuropsychological development might be attributable to chance. The associations found, although statistically significant, were based on small differences in mean test scores, and their clinical relevance remains to be determined.”

For more information on thimerosal, from the CDC, click here. Also, see my previous blogs on thimerosal:

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4 Responses to New Study Confirms that Mercury-Based Vaccines Don’t Hurt Children and are Safe

  1. Dan says:

    Autism is one of what I believe are a number of what are called passive developmental disorders- and autism is the most common. Autism is a disability caused by a brain development disorder of unknown cause, yet some suspect the cause is some sort of neurological dysfunction. Usually, symptoms of the disease present themselves before the toddler reaches the age of three. Before Autism was more understood, others labeled them as childhood schizophrenia or as having a psychosis or mental retardation.
    Out of 16 related characteristics, eight must be present to be considered autistic, according to others. As with all passive developmental disorders, the person expresses language, social, and behavioral difficulties. Treatment includes what are called psychotropic medications that delay the progression of the disorder, as well as relieve some of the symptoms of one who is autistic. Behavioral therapy is common as a treatment regimen as well. Boys get Autism much more than girls.
    Then there is the controversy between many who claim that thimerosal- a preservative containing mercury, which is a neurotoxin that was used in vaccines until 2001, was the catalyst for autism in children. Over 5000 lawsuits have been filed because of this belief, and some have been successful for the plaintiff. Yet most agree the correlation between thimersal and autism is void of scientific merit. Furthermore, the cases of autism have not decreased since the preservative was discontinued in 2001.
    Aside from Autism, the other four passive developmental disorders are known as autism spectrum disorders.
    Asperger’s Syndrome is more common than autism, and the symptoms are milder, as there is minimal delay in language abilities, if at all. What is expressed with Asperger’s syndrome is mild autistic symptoms. In time, the patient may express atypical personality disorders, though. While intelligence is within normal limits with the Asperger’s patient, social interactions and abilities preset difficulty for such a patient. As with Autism, medications and behavioral therapy are treatment regimens with one with this syndrome
    Rett’s Syndrome or disorder presents with not only atypical behavior, but also suffers from restricted physical growth and movement. There is cognitive and social impairment as well. The disorder affects mostly girls, and the cause is due to a gene mutation.
    Chldhood Disintegrative disorder is rare, and is 10 times less common than autism. The disorder has a late onset with mild autistic symptoms. The disorder affects mostly boys, and regression is sudden and possible with this disorder. Skills lost with this disorder may be language, social, self-care, as well as play or motor skills. Decreased function or impairment with this disorder may include social skills and behavioral flaws. Central Nervous System pathology is a suspected cause of this disorder.
    Finally, there are passive development disorders that are not otherwise specified. This may include atypical autism, for example. Yet as with the rest of types of these disorders, the symptoms vary in their intensity, and the range of abilities of these developmental disorders vary widely as well. Medicinal treatment along with cognitive and behavioral therapy prove to be most beneficial for all the different types of Passive Development Disorders that unfortunately exist for unknown reasons,

    Dan Abshear

  2. Lance says:

    Dr. Walt~
    I heard your comment today on KTIS about child abuse. You accused me of abusing my children for my decision to allow God’s beautiful creation to thrive, thereby not inhibiting that expression by polluting the body with chemicals. No, I’m not someone who was born in the back woods without an education. In fact I’m highly educated and have looked at both sides of the vaccine debate. You can have your opinion and I can have mine. However, I choose not to force my opinions on others or cause them to feel “wrong” or “abusers”, but instead, challenge them to look at the facts and make their own educated decision. My wife and I are absolutely disgusted by your comment about being “child abusers” for making an educated decision about our beautiful children’s health and well-being. You talk about one study and your “mountain of evidence” showing vaccines are safe. Have you looked at the other mountain range? I hope and pray that the people listening to your talk on KTIS today will not be warped into thinking there is only one way, but instead be led by God to search the evidence for themselves and make their own educated decisions on what is best for their children.

  3. Dr. Walt says:

    Lance,

    Thanks for taking the time to write. For more details on my accusation that parents who do not vaccinate their children are guilt of a form of child abuse (in my opinion), then you may want to see my blog entry on the topic. It’s at http://www.drwalt.com/blog/2009/02/04/radio-listeners-‘angry-as-hornets’-about-dr-walt’s-comments-on-childhood-vaccination/. Or just search for “angry as hornets.”

    I hope the information will assist you and your wife in making a wise decision regarding the raising and nurturing of highly healthy children.

    Blessings in your quest.

    Dr. Walt

  4. Dave Szum says:

    To those who do not vaccinate,

    As Lance points out, you are, of course, free to have your own opinion. The problem comes in when your actions start to put others at risk. The choice to not vaccinate opens the door to diseases that, for the most part, have been eradicated (at least in the US) through vaccination. One only has to look at history and the terrible childhood death rate that existed until the advent of the vaccine. I would venture to say that most of those folks thought their children beautiful and precious. But that did not stop the children from dying. All medication (whether it is vaccinations or pills) have side effects. If the side effect is worse than the symtpom, then certainly the medication should be avoided. In the case of vaccinations, the side effects typically involve a low fever (if at all). This side effect is actually somewhat anticipatible because it indicates that the immune response is working. In any case, the reason that not vaccinating seems to be a viable choice right now is that most of these diseases have been eradicated in the US. But it is only a matter of time before someone from a third world country brings it here and finds an unprotected person. The mortality rates of the more severe diseases are very high, and all the love in the world will not have much effect (if any) on the outcome. And all of the earnest beliefs that you are doing the right thing in not vaccinating will also have no effect on the outcome. So, yes, you can have your own opinion. But no one can force you to feel to feel “wrong” or “abusers”. Someone who states a ludicrous argument is not even considered seriously or laughed off. Usually, when you feel “wrong” it is because the other party has very valid points that are nagging you inside. Your emotional resentment is more of a response to that troubling feeling than it is to any difference of opinion. At the end of the day, Dr. Walt is trying to save the life of your child (whether it is in the near future or the farther future). And I think that that intention should be respected and valued. If he did not care, he would not waste his time with such stands. They are bound to be unpopular and, after all, none of us seek to be disliked.

    I would also like to put in a word about “research”. I am a professional research scientist and have learned some very real lessons about web searching. I have found that roughly 90% of the so-called research on web is merely opinion that is phrased to seem like fact. You must spend a lot of time and effort to dig out the well-controlled experiments and research that lead to the “golden needle” in the haystack. If you do not, then your research will lead you in the wrong direction with your decisions. In my case, if I take a wrong direction, my competitor gets a substantial advantage. In the case of vaccines, bad research may lead to death. And regret, like hindsight, does no one any good. Be forewarned!

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