This independent panel examined completed studies, on-going studies, published medical and scientific papers, and expert testimony to assess whether or not there was a link between autism and the MMR vaccine. Parents, scientists, and practitioners presented information on this topic to a multidisciplinary panel of experts. Based on its review, the AAP also found that the available evidence did not support the theory that the MMR vaccine caused autism or related disorders.
In , Taylor and colleagues published a study Taylor et al that argued against the suggested link between autism and the MMR vaccine suggested in the Wakefield study. Taylor's study looked at all the known cases of ASD in children living in certain districts of London who were born in , or later.
Researchers then matched the ASD patients with an independent registry of vaccinations. The results of this study showed that:. Also in , the United Kingdom's Committee on Safety of Medicine examined hundreds of reports collected by lawyers of patients with autism and similar disorders that families said they developed after receiving the MMR or MR vaccine.
After a systematic, standardized review of the case information, the Committee found that the information did not support any link between vaccines and autism. A study, done in Sweden in , also showed no evidence of association between the MMR vaccine and autism. The study compared the number of autism cases in children from two Swedish towns before , when local doctors first started using the MMR vaccine, and after Another study, done in England in , looked at any possible link between the measles-specific vaccine one part of the MMR vaccine and different problems that result from damage to the nervous system, such as learning disabilities and behavior problems.
These researchers found no proof that the measles vaccine was in any way linked to long-term damage to the nervous system Miller et al This Act, which was signed into law in October , charges the NIH with the, "Expansion, intensification, and coordination of activities of the NIH with respect to research on autism. In addition, the NIH will form a committee with representatives from parents' groups and other federal agencies to coordinate autism research activities throughout the federal government and to enhance efforts to educate doctors and other health care professionals, and parents, and other child caretakers, about autism.
The diseases that the MMR vaccine prevents, measles, mumps, and rubella also called German measles , are actually very serious. Many times, the symptoms and effects of these diseases are just as serious and life-long as the symptoms of autism. In some cases, these diseases result in death. If people stop getting vaccines, the number of cases of these diseases will increase, and with it, the number of deaths and serious health problems.
Measles is a life-threatening disease that spreads quickly and easily. Before the vaccine was available in the U. The symptoms of measles include a rash, high fever, cough, runny nose, and watery eyes. But, if not treated, these seemingly mild symptoms can lead to conditions such as pneumonia, seizures, and water and swelling around the brain. For one-in to one-in-1, people, measles causes death.
High levels of immunization in the U. But in poorer countries of the world, where vaccines aren't as common, nearly , people died from causes related to measles in Mumps, which the MMR vaccine also protects against, was a major cause of deafness in children before doctors started using vaccines to prevent it. Even though it tends to be mild in children, mumps is dangerous for adults, with side effects that can include paralysis, seizures, and fluid in the brain.
Before the vaccine for mumps was available, there were about , cases of mumps each year in the U. In , there were only cases of mumps in the U.
The last disease prevented by the MMR vaccine, rubella, is harmful to pregnant women and their growing babies. If a pregnant woman gets rubella, her baby may develop a life-long condition that includes heart defects, mental retardation, and deafness. J Med Virol ; Investigators obtained blood from 15 children diagnosed with autism with developmental regression and a documented previous receipt of MMR vaccine.
Measles virus genome was not present in any of the samples tested. The authors concluded that measles vaccine virus was not present in autistic children with developmental regression. No effect of MMR withdrawal on the incidence of autism: a total population study. J Child Psychol Psychiatry ;46 6 The authors concluded that withdrawal of MMR in countries where it is still being used will not lead to a reduction in the incidence of ASD. MMR vaccination and pervasive developmental disorders: a case-control study.
Lancet ; The authors reviewed a major United Kingdom database for patients diagnosed with autism or other pervasive developmental disorders PDD over a year period and similarly aged patients without those diagnoses to determine if the receipt of MMR vaccination was associated with an increased risk of autism or other PDD. A population-based study of measles, mumps, and rubella vaccination and autism. N Engl J Med ; 19 No association was found between ages at the time of vaccination, the time since vaccination, or the date of vaccination and the development of autistic disorder.
Autism and measles, mumps, and rubella vaccine: no epidemiological evidence for a causal association. The authors determined whether the introduction of MMR vaccine in the United Kingdom in affected the incidence of autism by examining children born between and They found no sudden change in the incidence of autism after introduction of MMR vaccine and no association between receipt of the vaccine and development of autism. Materials in this section are updated as new information and vaccines become available.
The Vaccine Education Center staff regularly reviews materials for accuracy. You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family's personal health.
You should not use it to replace any relationship with a physician or other qualified healthcare professional. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult your physician or, in serious cases, seek immediate assistance from emergency personnel.
Vaccines and Autism. Contact Us Online. First study In , Andrew Wakefield and colleagues published a paper in the journal Lancet. Because MMR is administered at a time when many children are diagnosed with autism, it would be expected that most children with autism would have received an MMR vaccine, and that many would have received the vaccine recently.
The observation that some children with autism recently received MMR is, therefore, expected. However, determination of whether MMR causes autism is best made by studying the incidence of autism in both vaccinated and unvaccinated children. This wasn't done.
Although the authors claim that autism is a consequence of intestinal inflammation, intestinal symptoms were observed after , not before, symptoms of autism in all eight cases. Second study In , Wakefield and coworkers published a second paper examining the relationship between measles virus and autism.
However, the second Wakefield paper was also critically flawed for the following reasons: Measles vaccine virus is live and attenuated. After inoculation, the vaccine virus probably replicates or reproduces itself about 15 to 20 times. Measles vaccine virus is likely to be taken up by specific cells responsible for virus uptake and presentation to the immune system termed antigen-presenting cells or APCs.
Because all APCs are mobile, and can travel throughout the body including the intestine , it is plausible that a child immunized with MMR would have measles virus detected in intestinal tissues using a very sensitive assay. To determine if MMR is associated with autism, one must determine if the finding is specific for children with autism. Decreasing acceptance of MMR vaccination has led to outbreaks or resurgence of measles. Health-care providers have a vital role in maintaining confidence in vaccination and preventing suffering, disability, and death from measles and other vaccine-preventable diseases.
Keywords: ASD; MMR vaccine; autism; autism spectrum disorder; immunization; measles, mumps, and rubella vaccine; vaccination; vaccine safety. In an accompanying editorial, BMJ editor in chief Fiona Godlee and co-authors Jane Smith and Harvey Marcovitch examine the damage to public health caused by a tiny study based on parental recall with no control group — a study that turned out to be almost entirely fraudulent, but whose impact continues to this day.
Evidence is strong that the original study should not have been published not merely because it was poorly conducted, but also because it was a product of research fraud. MMR is not the only vaccine or vaccine component that has been targeted for scrutiny by those who suspect vaccination might be related to autism.
After the MMR controversy died down, critics turned their questions to thimerosal, a mercury-containing preservative used in some vaccines. Thimerosal had never been used in MMR, as antimicrobial agents are not used in live vaccines. In the late s lawmakers, environmentalists, and medical and public health workers became concerned about environmental exposures to mercury, particularly from consumption of fish.
With heightened attention to known and potential harmful effects of such exposures, the U. Food and Drug Administration FDA in requested that drug companies report on amounts of mercury in their products. The results for mercury in vaccines, in the form of thimerosal, exceeded FDA guidelines for exposures to the kind of mercury found in fish.
Mercury in fish appears in the form of methylmercury, which is not readily metabolized and excreted in the human body. It is known to cause, at certain levels of high exposure, harmful neurological effects. The mercury in thimerosal metabolizes in the body to ethylmercury, a compound that, while not widely studied at the time, was thought to be much less harmful than methylmercury.
The FDA had a dilemma: there were no recommendations for exposure to levels of ethylmercury. Should they apply the methylmercury guidelines to ethylmercury? Was there cause for concern about exposure to mercury in childhood vaccines?
Unable to answer these questions immediately, together with the American Academy of Pediatrics and other groups, they called for vaccine companies to reduce or eliminate the use of thimerosal in vaccines.
Additionally, studies were planned to investigate whether there were harmful effects in children exposed to the amount of mercury in vaccines. Activists and others became concerned about the safety of thimerosal at this point, and they posited that autism could be an outcome of exposure to mercury in vaccines. The Institute of Medicine undertook a comprehensive safety review of the issue.
Their preliminary report, published in , stated that the committee did not find enough evidence to support or reject a causal relationship between mercury in vaccines and neurodevelopmental disorders.
Today, thimerosal is no longer used in most childhood vaccines, though some forms of influenza vaccine available in multi-dose vials may contain the preservative. After thimerosal was removed from most vaccines, autism rates did not drop.
Rather, they continued to rise. One such target is the number of vaccines given to children. Many vaccines have been added to the childhood immunization schedule since the s, and some critics have voiced concern that this increase in vaccine exposure results in autism. However, no evidence of an association between increased exposure to vaccines and autism has appeared. Yet the amounts of aluminum used in vaccines are small in comparison to other exposures to aluminum, such as in breast milk and infant formula.
Aluminum in vaccines has not been implicated in any infant or childhood health problems. Most scientific and medical experts are satisfied that no connection exists between vaccines and autism and other neurodevelopmental disorders. Still, critics continue to question the issue. Not only do they question the relationship between MMR and thimerosal and autism, they bring up further culprits they believe might play a role in development of autism.
Researchers continue to examine these questions, but there is no evidence that these factors play a role in autism development. Most autism researchers hold that the causes of autism are many and include genetic and environmental factors, but do not involve vaccines. British researcher Andrew Wakefield, along with 12 co-authors, published a paper in the Lancet claiming evidence of measles virus in the digestive systems of autistic children.
In press conferences after the paper was published, Wakefield suggested a relationship between the MMR measles, mumps and rubella vaccine and autism. Wakefield then recommended that the combination MMR vaccine be suspended in favor of single-disease vaccinations given separately over time. Measles cases, meanwhile, began to rise: while only 56 cases were confirmed in Wales and England in , 1, were confirmed by Numerous epidemiological studies performed since have also provided additional evidence that no such link exists.
Subsequently, the Lancet formally retracted the paper; in May , Wakefield was banned from practicing medicine in Britain. Despite this and the lack of any evidence to support a link between vaccines and autism, some groups remain convinced of the allegations first raised by Wakefield in Article Menu [ ]. Vaccine Science [ ]. Biological Weapons, Bioterrorism, and Vaccines.
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