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Is Thimerosal Linked To Autism

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Medical Experts Weight In

US Court Finds No Link Between Vaccines, Autism

In addition, several studies reported by the U.S. Centers for Disease Control and Prevention offer assurance to parents that vaccines do not cause autism.

These studies evaluated eight vaccines and also looked at a child’s response to antigen development from several vaccines over the first two years of life. Plus, the CDC found that exposure to thimerosal, either early in life or in the womb, does not increase a childs risk.

Additional studies from Europe, the Institute of Medicine, and the American Academy of Pediatrics have confirmed what the CDC found the patient advocacy group Autism Speaks also agrees.

Even though the medical evidence strongly supports that vaccines do not cause autism, many parents find the data overwhelming or simply ignore it. Some parents do not follow their child’s vaccine schedule and skip immunization, a great cause for concern.

In a study from Kaiser Permanente published in JAMA Pediatrics researchers found evidence that among children aged 4 to 6, those with autism were “significantly less likely” to receive the full range of recommended vaccines compared with other children.

Autism Rise: Is It Something In The Environment

It may still be too soon to draw conclusions from the California data, says Sally Bernard, co-founder and executive director of SafeMinds, an organization that advocates “sensible action for ending mercury-induced neurological disorders.”

“Their conclusions rely on the younger age group of 3- to 5-year-olds,” Bernard tells WebMD. “So if you are looking at trends, it is premature to make such conclusions.”

Bernard is far less concerned about what the data do not show than about what they do show: autism rates are still going up.

“This tells us that because autism is steadily increasing, there is an environmental source,” she says. “You cannot use this data to rule out thimerosal as a factor. What you can say is there may be — and probably are — other environmental triggers that play a role. It is probable that exposure to these other factors may be increasing.”

If thimerosal does play a role in autism, it isn’t a big one, says Gary W. Goldstein, MD, president and CEO of Baltimore’s Kennedy Krieger Institute.

“The thimerosal is pretty much gone now, and autism rates are still going up,” Goldstein tells WebMD. “It just is not the case that thimerosal in vaccines is the primary cause for the increase in autism. Could there be 5% of children more susceptible to autism and the thimerosal just tipped them over the edge? Yes, but this study did not address that question.”

The Schechter study appears in the January issue of Archives of General Psychiatry.

Autism And Its Histories

The hypothesis that thimerosal-containing vaccines could explain the remarkable rise in the prevalence of autism arose not among environmental scientists but among the communities that have emerged over the past 20 years of parents and professionals caring for autistic children. Specifically, parents and clinicians who have framed autism in biomedical terms have been critical agents in promoting both the concept of theautism epidemic and the primacy of vaccines as its cause. The passion behind their arguments stems from a long history of advocacy on behalf of their children, often in the face of psychiatric theories perceived as parent blaming and inadequately funded developmental and educational resources in many communities.

In 1965, psychologist Bernard Rimland rejected the psychogenic model of autism in his ground-breaking Infantile Autism, proposing that the condition was instead rooted in biology. The collapse of the psychoanalytic model gave rise, however, to two rather different explanatory frameworks in its place. The ways in which these have diverged and have been embraced by different communities of parents and professionals is of critical importance to understanding the current debate over the existence of an autism epidemic.

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Whats Known About The Causes Of Autism

First, like cystic fibrosis or sickle-cell disease, autism has a genetic basis. Researchers found that when one identical twin had autism, the chance that the other twin had autism was about 90 percent for fraternal twins, the chance was less than 10 percent.

Second, although autism has a genetic basis, environmental factors can also cause the disease. For example, children whose mothers took thalidomide, a medication that used to be prescribed for nausea during pregnancy, had birth defects, including malformed ears and shortened limbs. But they also had a significantly greater incidence of autism than babies born to mothers who never took thalidomide. Thalidomide clearly caused autism, but only if mothers took it early in pregnancy. If mothers took thalidomide in the second or third trimester of pregnancy, their babies weren’t at increased risk of autism.

Read more about autism and vaccines.

Is Thimerosal Still Found In Vaccines

Autism: Characteristics, diagnosis, and understanding

Thimerosal has been removed or reduced to trace amounts in most vaccines, with the exception of the multi-dose vial of the seasonal flu shot. Thimerosal is added to multi-dose vials to help prevent overgrowth of bacteria.

For parents who prefer, preservative-free versions of the flu shot are available all you have to do is request it from your doctor or pharmacist. You may need to check with your insurance first to be sure they’ll pay for the preservative-free form.

Thimerosal used to be found in the hepatitis B, Haemophilus influenzae type B and diphtheria, tetanus, and pertussis vaccines, among others. The U.S. Food and Drug Administration has worked with vaccine manufacturers to eliminate thimerosal from vaccines recommended for children 6 years and younger. In many common childhood vaccines, thimerosol was never present.

Thimerosal is not present in any COVID vaccine issued for emergency use authorization in the U.S. To see a full list of ingredients for COVID-19 vaccines in the U.S., follow this link.

At this time, the only COVID-19 vaccine authorized for use in children is the Pfizer-BioNTech vaccine, and it is only used in children 16 years or older. Studies in younger populations are ongoing.

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Mr Trump: Dont Become The First Anti

A prime example of the distraction associated with the vaccine/autism myth is the role of mercury. Mercury is released into the environment, primarily and other things that have mercury in them. Every hour, 11 pounds of mercury are released into the environment this way. As this mercury is distributed into the environment, bacteria convert it into methylmercury. This type of mercury can accumulate in food sources, such as fish, and also in our bodies. A high level of methylmercury in the body can affect brain development in children.

Another form of mercury, ethylmercury, isnt found in the environment. Instead, it is created in labs and was used in making thimerosal, a preservative in vaccines. While research has exonerated thimerosal as a risk factor for autism, it has been removed from most vaccines given to children under 6. Ethylmercury does not accumulate in the body and does not pose the same public health threat as methylmercury.

Scientists agree that methylmercury and ethylmercury have different toxicological and biological profiles, and should not be used interchangeably.

Mercury emissions from burning coal and medical waste can be reduced, which would minimize the potential harm to our children. The already strained EPA has had success doing that, but in order to continue reducing mercury in the environment, its activities need to be supported, not diminished. Mercury in the environment is not an issue one government agency, or one country, can address alone.

How Is This Study Different Than Previous Studies On Thimerosal And Autism

To date, there have been several on the safety of thimerosal in vaccines. The data shows that the low doses of thimerosal in vaccines do not cause harm, although it may be associated with minor side effects, such as redness and swelling at the injection site, and rare allergic reactions.

This new study adds more comprehensive data to the existing science on the safety of thimerosal. It is the most thorough to date because it is the first time CDC has gathered and examined maternal data and the first time CDC has examined ASD along with the various autism subtypes.

The study included consultation by external experts and representatives of autism advocacy groups, used state-of-the art in-person evaluations administered by research staff trained by leading autism experts, and was based on well-documented data on exposure to thimerosal-containing products. The study controlled for many factors that could influence the risk of autism or receipt of immunizations. Moreover, the study provides the strongest evidence to date that immunization during pregnancy with thimerosal-containing vaccines, including flu vaccine, does not increase risk of ASD.

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Thimerosal Linked To Immune System Dysfunction

University of California, Davis
A team of cell biologists, toxicologists and molecular bioscientists has published a study connecting thimerosal with disruptions in antigen-presenting cells known as dendritic cells obtained from mice.

A team of cell biologists, toxicologists and molecular bioscientists at UC Davis has published a study connecting thimerosal with disruptions in antigen-presenting cells known as dendritic cells obtained from mice. The study provides the first evidence that dendritic cells show unprecedented sensitivity to thimerosal, resulting in fundamental changes in the immune system’s ability to respond to external factors.

“This is the first time that thimerosal has been shown to selectively alter the normal functions of dendritic cells,” said Isaac Pessah, a toxicologist with the UC Davis School of Veterinary Medicine, director of the Children’s Center for Environmental Health and Disease Prevention and senior author of the study. “Dendritic cells play pivotal roles in overcoming viral and bacterial invaders by coordinating the immune system’s overall combat response.” One dendritic cell can activate as many as 300 T-cells — white blood cells that help find and kill external agents that attack the immune system — making them the most effective immune system activators.

The study shows how intricate connections between calcium channels in dendritic cells change when exposed to thimerosal.

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We Watched The Movie Vaxxed So You Dont Have To

Do Vaccines Cause Autism?

But during the same period, a dozen new scientific findings were published on legitimate environmental factors, including toxic chemicals, maternal infection during pregnancy, and chronic stress. These rarely made headlines, with the media spotlight remaining on the myth. Yet knowledge and understanding of these real environmental factors could lead to actual therapies or ways to prevent the debilitating symptoms of autism.

The term environmental factor is often misunderstood and used incorrectly. Scientists consider anything that produces a biological or behavioral response that isnt strictly due to genes to be environmental. This includes what we eat and drink, what we breathe, what touches our skin, and the like. Also worth clarifying is the difference between a risk and a cause. A cause is something that makes a disease happen. Risk factors, by comparison, are things that act in concert to nudge us toward disease.

Specific criteria have been laid out to determine if something is a cause or a risk factor. So far, no single environmental factor has met the criteria for being a cause of autism. This indicates that environmental factors work together, or interact with genes, to lead to autism.

Here are a few examples of environmental factors that that have been linked to autism:

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Does Mercury Used In Vaccines Cause Autism

Thimerosal is a preservative that has been used in some vaccines since the 1930s . Thimerosal consists of 49% ethylmercury and some have suggested, partly because of the known effects of methylmercury as a toxic substance, that thimerosal delivered in vaccines causes autism to develop in some children. Much is known about the effects of the more dangerous methylmercury. Massive systemic damage can occur through excessive methylmercury exposure. The Food and Drug Administration has advised pregnant women, nursing mothers, and young children limit their intake of certain types of fish, like tuna, that tend to contain high levels of methylmercury in order to prevent excessive methylmercury consumption. Much less is known about ethylmercury, however, the CDC reports that the cumulative exposure to ethylmercury that occurred when thimerosal was used as a preservative in vaccines was less than the FDA and World Health Organization recommended maximum safe exposure to methylmercury. However, the EPAs more stringent guideline for methylmercury exposure was exceeded. Therefore, given the heightened concern over mercury exposure, the suggested link between thimerosal and autism, and technology that exists for eliminating ethylmercury from vaccines, thimerosal has been removed from all vaccines in the U.S. with the exception of certain flu vaccines. Research into this putative link to autism was, and still is, clearly warranted.

How Was This Study Conducted

CDC conducted a case-control study in three health care organizations that participate in the Vaccine Safety Datalink Project. The VSD was established in 1990 as a collaborative effort between CDCs Immunization Safety Office and nine heath care organizations to monitor immunization safety and address the gaps in scientific knowledge about rare and serious adverse events following immunization.

A total of 1,008 children participated in the study of these, 256 had ASD and 752 did not. The purpose of the study was to see if ethylmercury from thimerosal in vaccines or immunoglobulin products increased a childs risk of developing autism. Ethylmercury exposure of the children and their mothers was ascertained and evaluated for possible relationship to ASD or two subtypes of ASD autistic disorder and ASD with regression.

Thimerosal is a mercury-containing preservative that is added to multi-dose vials of vaccine to prevent contamination and growth of potentially harmful bacteria.

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Methylmercury And The Developing Brain

Methylmercury, the form of mercury linked most closely in the public mind with environmental pollution, has a history as public and infamous as the history of ethylmercury has been quiet and inconspicuous. Much in the thimerosal debate hinges on the alleged similarity, or dissimilarity, of ethylmercury to methylmercury. The two compounds sound alike, differ by only one methylated side chain in their structure, and tend to be mentioned interchangeably in the popular press. Yet the chemical distinction is not trivial it may be compared with that between ethanol and its highly lethal counterpart methanol. Methylmercury was once used widely in developing countries as a fungicide as part of the Green Revolution that transformed agriculture after 1945. It is also synthesized by bacteria living in mercury-polluted waters, where it is passed up the food chain and concentrated in fish. The dangers of methylmercury in both contexts have been vividly demonstrated in a series of environmental disasters.

What Are The Most Common Risk Factors For Autism

The link between thimerosal

ASD occurs among all racial, ethnic, and socioeconomic groups.

Common risk factors for autism spectrum disorder include:

  • Having a twin with ASD, or other family history.
  • Boys are about 4 times more likely to develop ASD than girls.
  • Parents who have had a child with ASD have a 2% to 18% chance of having another child with the disorder.
  • Children born to older parents also seem to have a higher risk, but more research is necessary.
  • About 10% of children with autism also have certain genetic disorders like Rett Syndrome or fragile X syndrome, or tuberous sclerosis, where benign tumors develop in the brain.
  • Preterm babies born before 26 weeks of gestation may have an elevated risk of autism spectrum disorder.
  • Over 80% of children diagnosed with ASD also have a psychiatric, neurologic, chromosomal, or genetic diagnosis.

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Are Vaccines Linked To Autism

The topic of childhood vaccines leading to autism spectrum disorder is one that never seems to fades away.

Concerns about vaccines leading to autism surfaced in 1999 and initially involved the measles, mumps and rubella vaccine.

Because the MMR vaccine is usually given at age 12 to 15 months, and the first signs of autism often appear at this time, concerns were raised about a link between the MMR vaccine and the development of autism.

The Centers for Disease Control and Prevention has conducted 9 studies that have found no association between thimerosal-containing vaccines and ASD, or between the measles, mumps, and rubella vaccine and ASD in children.

In 2019, in the largest study ever published on this topic, investigators found no evidence that the measles, mumps and rubella vaccine causes autism when looking at over 650,000 Danish children. This result held true even when researchers focused on children at greater risk for developing autism. The results were published in the Annals of Internal Medicine.

Unfortunately researchers are skeptical the new data will change the mind of so-called “anti-vaxxers”. However, they feel the large study might provide reassurance to certain parents who are willing to listen to science.

Scientific Research Does Not Show A Connection Between Thimerosal And Autism

Research does not show any link between thimerosal in vaccines and autism, a neurodevelopmental disorder. Many well conducted studies have concluded that thimerosal in vaccines does not contribute to the development of autism. Even after thimerosal was removed from almost all childhood vaccines, autism rates continued to increase, which is the opposite of what would be expected if thimerosal caused autism.

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Beyond The Autism/vaccine Hypothesis: What Parents Need To Know About Autism Research

A decade ago most researchers agreed that we needed to study vaccines in relation to autism. We had to reconcile the fact that the number of vaccines children were receiving was increasing, and at the same time, the number of children who were being diagnosed with autism also was on the rise. Fortunately this was a question that could be studied and answered by science. We looked at children who received vaccines and those who didnt, or who received them on a different, slower schedule. There was no difference in their neurological outcomes. Multiple studies have been completed which investigated the measles, mumps and rubella vaccination in relation to autism. Researchers have also studied thimerosal, a mercury-based preservative, to see if it had any relation to autism. The results of studies are very clear the data show no relationship between vaccines and autism. Read the studies themselves below and browse our recommended reading list.

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