Autism is a neurological disease which impacts the ability of a person to communicate. Autism is known to be a group of several disorders which impacts the communicating and relating ability of the person. It is not a single disease but rather a description for a group of disorders that affect people in similar ways. This condition is also referred as autism spectrum disorders (ASD). The origin of autism causes several controversies due to the fact that it’s origin is largely unidentified presently. Autism is possibly caused due to an amalgamation of environmental triggers and genetic factors. Defective immune system is reported to be responsible for autism whereas environment pollutants are also held responsible for the disease. The childhood vaccination has also been a topic of debate and discussion for being the causative agent of autism.
The first signs of autism generally appear in the second year of life, which coincides with the MMR vaccination. Autism has never been linked with the measles vaccine and the concern arose with the introduction of mumps and rubella to produce a triple vaccine. Mainly, the association of autism with MMR vaccine is based on three observations. First, was the observation that the children who diagnosed with disease autism, their number increased considerably simultaneously with the introduction of MMR vaccine in the Britain and United States. Study by Wakefield et al in 1998 published its results in scientific journal Lancet and provided the second observation of the positive association of MMR and autism . Third observation was that autism were diagnosed in children after their receiving MMR vaccine.
Considering the first observation, diagnosis of the number of children with autism escalated radically almost about the similar time to the introduction of MMR vaccine in 1971. The similar timing led to the conclusion about the positive correlation between MMR vaccine and autism. However, this association is not rational as the frequency of diagnosis of autism children increased in 1970s due to the proper identification of the disease. Before 1990s, definition of autism was narrow and it underwent changes twice on year 1987 and year 1994 stated by American Psychiatric Association . DSM III and DSM IV provided increasingly accurate description of autism leading to the accurate diagnosis of children with autism. This enabled the medical practitioners to differentiate between mentally retarded and autistic children, which increased the number of autistic children and reduced the frequency of them being regarded as mentally retarded. This results in correct diagnosis of autistic children in present time. Moreover, autism was not an understood disease in 1980s and majority of doctors were not educated on this condition, leading to incorrect diagnosis of autism. Hence, this can be stated that the event of recognition of children with autism happened simultaneously to the introduction of MMR vaccine however this doesn’t lead to establishment of the positive association of autism with the MMR vaccine.
The second observation regarding MMR vaccine and autism was the study by Wakefield et al (1998). The study involved twelve children who supposedly demonstrated symptoms of delayed development after administration of the MMR vaccine. The study hypothesized that MMR vaccine triggers intestinal inflammation which consequently allows damaging proteins to penetrate the brain and the bloodstream. The study stated that these damaging proteins impact the brain and causes autism. The study recommended the separation of MMR vaccine into separate vaccines for measles, mumps and rubella to avoid intestinal inflammation, although no substantiation that extrication the vaccine would not lead to intestinal inflammation was provided.
Alternatively, Dr. Honda et al (2005) demonstrated that children sustained development of autism in the absence of MMR vaccine . Due to the concern over the potential side effects of vaccines, MMR vaccine wasn’t recommended to children in Yokohama, a city of Japan from year 1988 to year 1996. From 1993, not even a single child in city received the MMR vaccine and despite of this, the children with autism were identified in the city of Japan. In fact, the statistics revealed that the number of children with autism from 1993 actually doubled in comparison to the autistic children diagnosed before stopping the vaccination. The study concluded that the vaccination was not related to autism as has been demonstrated in the study by Wakefield et al. Several other researchers also established the fact that autism was not caused due to MMR vaccine .
The third correlation of autism with vaccination that the autism was always diagnosed after the administration of MMR vaccination was rejected based on the fact that autistic children are identified when their language skills doesn’t match with the fluency and standard of the normal children which occurs almost at the same time of MMR vaccination. Moreover, presently with the increased knowledge of autism, some experts are able to diagnose children with autism at the age of six months, way before the MMR vaccination.
Apart from MMR vaccine, thimerosal was also reported to be the causative agent of the autism in children. Thimerosal is a mercury based preservative which was used in child vaccination before 2001. Due to the denial of parents to administer these vaccines to their children, thimerosal was removed from all the vaccines by 2001 to ensure adherence to vaccination schedule. Several studies were conducted to identify thimerosal as the source of autism in children; however none could establish the positive association between the two . The children vaccinated with thimerosal exhibited similar chances to develop autism as the children who were not vaccinated.
Another hypothesis linking autism with vaccination was reported to be the assumption that too many vaccines led to the development of autism in children. Another study was carried out comparing the rates of autism and other neuro-developmental or psychological disorders in children who were vaccinated according to the recommended schedule with the rates in children whose parents had chosen to delay or withhold vaccines . There was no difference found between the two groups. Delaying or withholding the vaccines didn’t lessen the risk of autism.
Based on the above observations, it can be stated that autism in the children is not related to vaccination though several theories have been put forth identifying vaccinations as the possible cause of the autism. MMR vaccines, thimerosal and frequency of vaccines at varies times have been considered as the causative agent of the autism though through experimental studies, no association between vaccines and autism was established. Moreover, the primary study by Wakefield which laid the foundation of MMR vaccine as responsible agent for autism was proved to be compromised and rejected by the ethical committee, hence though the cause of autism is still unclear, it can’t be accorded to vaccines.
References
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H. Honda, Y. Shimizu & M. Rutter. (2005). No Effect of MMR Withdrawal on the Incidence of Autism: A Total Population Study. Journal of Child Psychiatry and Psychology , 46, 572-579.
J. Heron & J. Golding. (2004). Thimerosal Exposure in Infants and Developmental Disorders: A Prospective study in the United States does not support a casual association. Pediatrics , 114, 577-583.
M.J. Smith, C.R. Woods. (2010). On-Time Vaccine Receipt in the First Year Does Not Adversely Affect Neuropsychological Outcomes. Pedistrics , 125, 1-8.
P.A. Offit & S.E. Coffin. (2003). Communicating Science to the Public; MMR Vaccine and Autism. Vaccine , 22, 1-6.
Wakefield et al. (1998). IIleal lymphoid nodular hyperplasia, non-specific coilitis, and pervasive development disorder in children. The Lancet , 351, 637-641.
Wakefield, A. (2002). Enterocolitis, autism and measles virus. Molecular Psychiatry , 7, 544-546.
