Do Vaccines Cause Autism Spectrum Disorder?
No. A 1998 study that claimed Autism Spectrum Disorder was caused by the measles, mumps and rubella (MMR) vaccine was based on faulty research and was later retracted. Meanwhile, several other more recent studies show vaccines have no connection at all to autism — but they do lower kids’ risks of getting dangerous health conditions like whooping cough and polio.
Autism rates in developing countries have risen remarkably in the past 20 years. For children born in 1992, according to the U.S. CDC, about 1 in 150 would be diagnosed with an autism spectrum disorder (ASD). For children born in 2004, about 1 in 68 children would receive an ASD diagnosis. It is difficult to compare autism rates from the 1990s and later with rates from the 1940s through the 1980s: in earlier years, autism was associated primarily with very severely affected individuals and the rate of autism was estimated to be only about 1 in 10,000 people. Beginning in the 1990s, our understanding of the spectrum of autism has expanded greatly, and now individuals who would most likely previously not have been thought of as having autism may be classified with one of a variety of ASDs.
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. Regardless, researchers and worried parents alike have speculated about causes of autism, and the issue has been widely studied. 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 than any other speculated the 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. Some, however, still question whether vaccines play a role in ASD development, and so the public health and medical establishments continue to address these concerns.
The paper’s findings led other doctors to do their own research into the link between the MMR vaccine and autism. At least 12 follow-up studies were done. None found any evidence the vaccine caused autism.
An investigation into the 1998 study also uncovered a number of problems with how it was conducted. The journal that published it eventually retracted it. That meant the publication no longer stood by the results.
Many studies that have looked at whether there is a relationship between vaccines and autism spectrum disorder (ASD). To date, the studies continue to show that vaccines are not associated with ASD.
However, CDC knows that some parents and others still have concerns. To address these concerns, CDC is part of the Inter-Agency Autism Coordinating Committee (IACC), which is working with the National Vaccine Advisory Committee (NVAC) on this issue. The job of the NVAC is to advise and make recommendations regarding the National Vaccine Program. Communication between the IACC and NVAC will allow each group to share skills and knowledge, improve coordination, and promote better use of research resources on vaccine topics.
Although child vaccination rates remain high, some parental concern persists that vaccines might cause autism. Three specific hypotheses have been proposed: (1) the combination measles-mumps-rubella vaccine causes autism by damaging the intestinal lining, which allows the entrance of encephalopathic proteins; (2) thimerosal, an ethylmercury-containing preservative in some vaccines, is toxic to the central nervous system; and (3) the simultaneous administration of multiple vaccines overwhelms or weakens the immune system. We will discuss the genesis of each of these theories and review the relevant epidemiological evidence.