This dramatic event followed the revelation that Wakefield had accepted money from lawyers representing parents who had filed lawsuits claiming that the MMR vaccines had caused autism in their children. Some of these children were even part of Wakefield's original study. (Schreibman, 2005)
This disclosure may have laid some doubts to rest but is still not enough to answer the question whether there is actually a link between MMR and autism. Firstly, there is a doubt amongst parents and scientists whether MMR may cause measles, encephalitis or a depression of the immune system in general. However, numerous studies have looked into this possibility and have concluded that the chance is extremely less at the rate of
It is true that there has been a rise in the cases of autism in the U.S. As per CDC data, prevalence of autism in Brick Township, New Jersey, has gone up to 40 per thousand. However, the rise may be attributed to many other factors like small size of population under study, greater awareness of autism and other disorders in the community, higher intensity of case-finding techniques, and the utilization of diagnostic tools like ADOS-G or Autism Diagnostic Observation Schedule-G, which may have resulted in mildly autistic children also being included in the survey. (Stratton; Institute of Medicine (U.S.); Board on Health Promotion and Disease Prevention; Gable, 2001)
An interesting observation was reported in a few studies conducted in Japan. Now, Japan is quite atypical amongst developed nations since its primary source of measles prevention is not MMR. Japan started using MMR only in 1989 but had to withdraw it in 1993 following claims of meningitis cases related to the Urabe mumps strain present in the vaccine. The initial uptake of MMR vaccine in Japanese children born in 1988 was as much as 70% but there was a gradual decline in this rate till 1993. A study conducted by Honda et al. presented a hypothesis that in case MMR vaccine did cause autism, then there should have been a logical increase in the number of autism cases after 1989 when MMR was introduced followed by a gradual decline in reported cases of autism after 1993 when MMR was withdrawn. The area under study had good diagnostic practices and advanced services for identification of developmental delays. The researchers found that cases of autism continued to rise in the period under study irrespective of the fact that MMR was withdrawn. Obviously, MMR vaccination was not to blame for the rising cases of autism. Of course, apart from the Wakefield report, there have been other studies which have reportedly found an association between MMR and autism. However, many of such studies have been found to have methodological flaws or some biases. (Jepson; Johnson, 2007)
The persistent debate over the MMR-autism controversy and the misleading medical opinion of a significant group of physicians about the safety of administering MMR has confused parents. This has led to many parents choosing not to immunize their children against these three diseases. This can have serious fallouts since unvaccinated children definitely have a higher chance of contracting these diseases. In fact, Ireland has reported cases of death occurring in unvaccinated children due to mumps, measles or rubella. Moreover, these diseases are highly contagious and can travel long distances from a place where there are low immunization rates. If a population is well vaccinated, such a threat does not exist at all. One of the most alarming facts is that pregnant women who get exposed to unvaccinated children suffering from mumps, measles or rubella, have a heightened risk of exposing their unborn children to the viruses which leads to birth defects in the fetuses. In fact, exposure of pregnant women to rubella is believed to cause autism in the child. (Fitzpatrick, 2004); (Doyle; Iland; Future Horizons Inc., 2004)
Most of the epidemiological studies conducted till date has proved to be inadequate in giving a complete answer despite the obvious lack of connection between MMR and autism. A number of scientists think that there might be a "temporal relationship" between MMR immunization and the appearance of autism which means that their timing are the same but since a cause-and-effect relationship has not been established the occurrence of autism symptoms and MMR timing can be scientifically considered as a coincidence and nothing else. (Doyle; Iland; Future Horizons Inc., 2004); (Jepson; Johnson, 2007) as for the few missing links, research has ruled out the association between MMR and autism but further research may be required to look into other aspects of the matter like the actual causes of autism and the missing links that exist in the MMR-autism debate. (Fitzpatrick, 2004)
Bauman, Margaret L; Kemper, Thomas L. (2005) "The neurobiology of autism"
Centers for Disease Control and Prevention. (2008) "Measles, Mumps, and Rubella
(MMR) Vaccine" Retrieved 25 March, 2009 from http://www.cdc.gov/vaccinesafety/concerns/mmr_vaccine.htm
Doyle, Barbara T; Iland, Emily Doyle; Future Horizons Inc. (2004) "Autism Spectrum
Disorders from a to Z" Future Horizons.
Fitzpatrick, Michael. (2004) "MMR and Autism"
Jacobson, John W; Foxx, Richard M; Mulick, James Anton. (2005) "Controversial
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Jepson, Bryan; Johnson, Jane. (2007) "Changing the Course of Autism" Sentient