MMR Vaccine Controversy - Research

Research

The number of reported cases of autism increased dramatically in the 1990s and early 2000s. This increase is largely attributable to changes in diagnostic practices; it is not known how much, if any, growth came from real changes in autism's prevalence, and no causal connection to the MMR vaccine has been demonstrated. The following were published after the 1998 Wakefield et al. paper:

• In October 2004, a meta review, financed by the European Union, was published in the October 2004 edition of Vaccine that assessed the evidence given in 120 other studies and considered unintended effects of the MMR vaccine. The authors concluded that although the vaccine is associated with positive and negative side effects, a connection between MMR and autism was "unlikely".

• In February 2005, a study compared autism in Japan before and after the 1993 withdrawal of the MMR vaccine: the autism rates continued to increase, which means that the withdrawal of MMR in other countries is unlikely to cause a reduction in future autism cases.

• A 2007 case study used the figure in Wakefield's 1999 letter to The Lancet alleging a temporal association between MMR vaccination and autism to illustrate how a graph can misrepresent its data, and gave advice to authors and publishers to avoid similar misrepresentations in the future.

• A 2007 review of independent studies performed after the publication of Wakefield et al.'s original report found that these studies provide compelling evidence against the hypothesis that MMR is associated with autism.

• A review of the work conducted in 2004 for UK court proceedings but not revealed until 2007 found that the polymerase chain reaction analysis essential to the Wakefield et al. results was fatally flawed due to contamination, and that it could not have possibly detected the measles that it was supposed to have detected.

• A 2009 review of studies on links between vaccines and autism discusses the MMR vaccine controversy as one of three main hypotheses which epidemiological and biological studies fail to support.

• In February 2012, the Cochrane Library published a review of dozens of scientific studies involving in all about 14,700,000 children, which found no credible evidence of an involvement of MMR with either autism or Crohn's disease. However the authors of the report also stated that "the design and reporting of safety outcomes in MMR vaccine studies, both pre- and post-marketing, are largely inadequate."