Which immunizations cause autism

Measles is an extremely contagious disease caused by a virus from the paramyxovirus family and spread by air. Top 20 Questions about Vaccination. Detailed answers to the most frequently asked questions about vaccination. History of Anti-vaccination Movements. Though many consider vaccination a top public health achievement of modern medicine, opposition to vaccination dates back to its introduction in the early s. Boy with measles Centers for Disease Control and Prevention.

Autism rates in developing countries have risen remarkably in the past 20 years. For children born in , according to the U. For children born in , about 1 in 68 children would receive an ASD diagnosis. Whether the high rates of autism today are due to increased diagnosis and reporting, changing definitions of autism, or an actual increase in development of ASD is unknown.

The role of vaccines has been questioned, along with other possible risk factors for ASD, such as genetic predisposition, advanced parental age, and other environmental factors. Vaccines have perhaps received more scrutiny that any other speculated cause of ASD, and the great majority of scientists, physicians, and public health researchers have come to the conclusion that there is no association between vaccines and autism.

The story of how vaccines came to be questioned as a cause of autism dates back to the s. In , a group of British researchers published a cohort study in the Lancet showing that individuals who had been vaccinated with the measles-mumps-rubella vaccine MMR were more likely to have bowel disease than individuals who had not received MMR.

Part of this hypothesis — that vaccination was associated with autism — had been suggested previously a few researchers.

For example, Fudenberg, in a small pilot study published in a non-mainstream journal, posited this relationship[8], as did Gupta in a review of possible treatments for autism. In , Wakefield, along with 12 co-authors, published a case series study in the Lancet claiming that they found evidence, in many of the 12 cases they studied, of measles virus in the digestive systems of children who had exhibited autism symptoms after MMR vaccination.

Wakefield himself had filed for a patent for a single-antigen measles vaccine in and so would seem to have a potential financial interest in promoting this view. Reaction to the Wakefield publication was immediate. Press outlets covered the news widely and frightened parents began to delay or completely refuse vaccination for their children, both in Britain and the United States.

MMR vaccination rates in Britain plummeted. Over the next twelve years, the possibility of a link between MMR and autism was studied exhaustively. In , then-editor Dr.

Richard Horton of the Lancet wrote that Wakefield should have revealed to the journal that he had been paid by attorneys seeking to file lawsuits against vaccine manufacturers. After examining the records for all twelve children, Deer noted that the statements made in the paper did not match numbers from the records in any category: the children having regressive autism; those with non-specific colitis; or those showing first symptoms within days after receiving the MMR vaccine.

The Lancet paper claimed that six of the children had all three of these conditions; according to the records, not a single child actually did.

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.

Vaccines are not associated with autism: An evidence-based meta-analysis of case-control and cohort studies external icon external icon Vaccine. Schechter R, Grether JK. Institute of Medicine. Immunization Safety Review. Association between thimerosal-containing vaccine and autism external icon. A population-based study of measles, mumps, and rubella vaccination and autism external icon.

N Engl J Med. An assessment of thimerosal in childhood vaccines external icon. Skip directly to site content Skip directly to page options Skip directly to A-Z link.

Vaccine Safety. Section Navigation. Facebook Twitter LinkedIn Syndicate. Autism and Vaccines. Minus Related Pages. Questions and Concerns. Since then, numerous scientific studies have shown that there is no link between vaccines — or any of their ingredients — and autism. And the research used in that study was found to be false, the doctor who wrote it lost his medical license, and the medical journal that published it retracted the paper this means that they believe it never should have been published.

Even with the overwhelming evidence that vaccines are safe and effective, some parents still decide not to have their children vaccinated or to delay vaccinations. But this is extremely risky because vaccine-preventable diseases like measles are still around.

An unvaccinated child who gets one of these preventable diseases could get very sick or even die , as could other people around the child.