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Vaccines and autism

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Extensive investigation into vaccines and autism[1] has shown that there is no relationship between the two, causal or otherwise,[1][2][3] and that vaccine ingredients do not cause autism.[4] Vaccinologist Peter Hotez researched the growth of the false claim and concluded that its spread originated with Andrew Wakefield's fraudulent 1998 paper, with no prior paper supporting a link.[5]

Despite the scientific consensus for the absence of a relationship,[1][2] the retracted paper and the anti-vaccination movement at large continue to promote myths, conspiracy theories, and misinformation linking the two.[6] A developing tactic appears to be the "promotion of irrelevant research [as] an active aggregation of several questionable or peripherally related research studies in an attempt to justify the science underlying a questionable claim."[7]

Claimed mechanisms[edit]

The claimed mechanisms have changed over time, in response to evidence refuting each in turn.[8]

Vaccine-derived measles virus[edit]

The idea of a link between the MMR vaccine and autism came to prominence after the publication of a paper by Andrew Wakefield and others in The Lancet in 1998. This paper, which was retracted in 2010 and whose publication led to Wakefield being struck off the UK medical register, has been described as "the most damaging medical hoax of the last 100 years".[9]

Wakefield's core claim was that he had isolated evidence of vaccine-strain measles virus RNA in the intestines of autistic children, leading to a condition he termed autistic enterocolitis (this was never recognised or adopted by the scientific community). This finding was later shown to be due to errors made by the laboratory where the polymerase chain reaction (PCR) tests were performed.[citation needed]

The CDC,[10] the IOM of the National Academy of Sciences,[11] and the UK National Health Service[12] have all concluded that there is no evidence of a link between the MMR vaccine and autism. A systematic review by the Cochrane Library concluded that there is no credible link between the MMR vaccine and autism, that MMR has prevented diseases that still carry a heavy burden of death and complications, that the lack of confidence in MMR has damaged public health, and that the design and reporting of safety outcomes in MMR vaccine studies are largely inadequate.[13]

In 2009, The Sunday Times reported that Wakefield had manipulated patient data and misreported results in his 1998 paper, creating the appearance of a link with autism.[14] A 2011 article in the British Medical Journal described how the data in the study had been falsified by Wakefield so that it would arrive at a predetermined conclusion.[15] An accompanying editorial in the same journal described Wakefield's work as an "elaborate fraud" that led to lower vaccination rates, putting hundreds of thousands of children at risk and diverting energy and money away from research into the true cause of autism.[16]

A special court convened in the United States to review claims under the National Vaccine Injury Compensation Program ruled on February 12, 2009 that parents of autistic children are not entitled to compensation in their contention that certain vaccines caused autism in their children.[17]

Thiomersal[edit]

Thiomersal (spelled "thimerosal" in the US) is an antifungal preservative used in small amounts in some multi-dose vaccines (where the same vial is opened and used for multiple patients) to prevent contamination of the vaccine.[18] Thiomersal contains ethylmercury, a mercury compound which is related to, but significantly less toxic than, the neurotoxic pollutant methylmercury. Despite decades of safe use,[19] public campaigns prompted the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP) to request vaccine makers to remove thiomersal from vaccines as quickly as possible on the precautionary principle. Thiomersal is now absent from all common US and European vaccines, except for some preparations of influenza vaccine.[20] (Trace amounts remain in some vaccines due to production processes, at an approximate maximum of 1 microgramme, around 15% of the average daily mercury intake in the US for adults and 2.5% of the daily level considered tolerable by the WHO.[21][22]) The action sparked concern that thiomersal could have been responsible for autism.[20]

The idea that thiomersal was a cause or trigger for autism is now considered disproven, as incidence rates for autism increased steadily even after thiomersal was removed from childhood vaccines.[8] There is no accepted scientific evidence that exposure to thiomersal is a factor in causing autism.[23]

Under the FDA Modernization Act (FDAMA) of 1997, the FDA conducted a comprehensive review of the use of thimerosal in childhood vaccines. Conducted in 1999, this review found no evidence of harm from the use of thimerosal as a vaccine preservative, other than local hypersensitivity reactions.[24] Despite this, starting in 2000, parents in the United States pursued legal compensation from a federal fund arguing that thiomersal caused autism in their children.[25] A 2004 Institute of Medicine (IOM) committee favored rejecting any causal relationship between thiomersal-containing vaccines and autism[11] and rulings from the vaccine court in three test claims in 2010 established the precedent that thiomersal is not considered a cause of autism.[26][27][28]

Vaccine overload[edit]

Following the belief that individual vaccines caused autism was the idea of vaccine overload, which claims that too many vaccines at once may overwhelm or weaken a child's immune system and lead to adverse effects.[29] Vaccine overload became popular after the Vaccine Injury Compensation Program accepted the case of nine year old Hannah Poling. Hannah had encephalopathy putting her on the autism spectrum disorder, which was believed to have worsened after getting multiple vaccines at nineteen months old.[8] There have been multiple cases reported similar to this one, which led to the belief that vaccine overload caused autism. However, scientific studies show that vaccines do not overwhelm the immune system.[8] In fact, conservative estimates predict that the immune system can respond to thousands of viruses simultaneously.[8] It is known that vaccines constitute only a tiny fraction of the pathogens already naturally encountered by a child in a typical year.[8] Common fevers and middle ear infections pose a much greater challenge to the immune system than vaccines do.[30] Other scientific findings support the idea that vaccinations, and even multiple concurrent vaccinations, do not weaken the immune system[8] or compromise overall immunity[31] and, furthermore, evidence that autism has any immune-mediated pathophysiology has still not been found.[8]

Aluminium[edit]

Since mercury compounds in vaccines have been definitively ruled out as a cause of autism, some anti-vaccine activists propose aluminium salts as the cause of ASD.[32] This is based in part on the erroneous popular belief that aluminium causes Alzheimer disease.[33] There is no good scientific evidence that aluminium salts are linked to autism, but anti-vaccination activists commonly cite a number of papers which claim that there is in fact a link.[34] These are mainly published in predatory open access journals,[35] where peer-review is virtually non-existent. One, in the mainstream Journal of Inorganic Biochemistry, was subsequently retracted.[36] Work conducted by Christopher Shaw, Christopher Exley and Lucija Tomljenovic has been funded by the anti-vaccination Dwoskin Family Foundation.[37] The work published by Shaw et al. has been discredited by the World Health Organization.[38]

Celebrity involvement[edit]

Jenny McCarthy speaking against the use of vaccines. She remains convinced that they caused autism in her son.

Some celebrities have spoken out on their views that autism is related to vaccination, including: Jenny McCarthy, Kristin Cavallari,[39] Toni Braxton,[39] Robert De Niro,[40] Jim Carrey,[41] Bill Maher,[42] and Robert F. Kennedy, Jr.[43] Kennedy in particular published the book Thimerosal: Let the Science Speak: The Evidence Supporting the Immediate Removal of Mercury--A Known Neurotoxin--From Vaccines.[44]

McCarthy, one of the most outspoken celebrities on the topic, has said her son Evan's autism diagnosis was a result of the MMR vaccine, despite the comprehensive evidence to the contrary.[45] She authored Louder than Words: A Mother's Journey in Healing Autism and co-authored Healing and Preventing Autism.[46] She also founded an organization called Generation Rescue, which provides resources for families affected by autism.[47]

In a September 2015 CNN Presidential debate, Donald Trump claimed to know of a 2-year-old who recently got a combined vaccine, developed a fever, and is now on the autism spectrum.[48]

References[edit]

  1. ^ a b c Taylor LE, Swerdfeger AL, Eslick GD (June 2014). "Vaccines are not associated with autism: an evidence-based meta-analysis of case-control and cohort studies". Vaccine. 32 (29): 3623–9. doi:10.1016/j.vaccine.2014.04.085. PMID 24814559.
  2. ^ a b Bonhoeffer J, Heininger U (June 2007). "Adverse events following immunization: perception and evidence" (PDF). Current Opinion in Infectious Diseases. 20 (3): 237–46. doi:10.1097/QCO.0b013e32811ebfb0. PMID 17471032.
  3. ^ Boseley S (February 2, 2010). "Lancet retracts 'utterly false' MMR paper". The Guardian. Retrieved February 2, 2010.
  4. ^ "Vaccines Do Not Cause Autism Concerns". Centers for Disease Control and Prevention. 2018-12-12. Retrieved 2019-02-07.
  5. ^ J., Hotez, Peter. "Vaccines did not cause Rachel's autism : my journey as a vaccine scientist, pediatrician, and autism dad". ISBN 9781421426600. OCLC 1020295646.
  6. ^ Cummins, Eleanor. "How autism myths came to fuel anti-vaccination movements A timeline leading to the 2019 measles outbreaks". Popular Science.
  7. ^ Foster CA, Ortiz SM (February 2016). "Vaccines, Autism, and the Promotion of Irrelevant Research: A Science-Pseudoscience Analysis". Skeptical Inquirer. 41 (3): 44–48. Archived from the original on 2018-10-06. Retrieved 6 October 2018.
  8. ^ a b c d e f g h Gerber JS, Offit PA (February 2009). "Vaccines and autism: a tale of shifting hypotheses". Clinical Infectious Diseases. 48 (4): 456–61. doi:10.1086/596476. PMC 2908388. PMID 19128068. Lay summaryIDSA (2009-01-30).
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  10. ^ "Concerns about autism". Centers for Disease Control and Prevention. 2010-01-15.
  11. ^ a b Immunization Safety Review Committee (2004). Immunization Safety Review: Vaccines and Autism. The National Academies Press. doi:10.17226/10997. ISBN 978-0-309-09237-1. PMID 20669467.
  12. ^ MMR Fact Sheet Archived June 15, 2007, at the Wayback Machine, from the United Kingdom National Health Service. Retrieved June 13, 2007.
  13. ^ Di Pietrantonj, Carlo; Rivetti, Alessandro; Marchione, Pasquale; Debalini, Maria Grazia; Demicheli, Vittorio (20 April 2020). "Vaccines for measles, mumps, rubella, and varicella in children". The Cochrane Database of Systematic Reviews. 4: CD004407. doi:10.1002/14651858.CD004407.pub4. ISSN 1469-493X. PMC 7169657. PMID 32309885.
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  16. ^ Godlee F, Smith J, Marcovitch H (January 2011). "Wakefield's article linking MMR vaccine and autism was fraudulent". BMJ. 342: c7452. doi:10.1136/bmj.c7452. PMID 21209060.
  17. ^ Vaccine court and autism:
    • "Vaccine didn't cause autism, court rules". CNN. 2009-02-12. Retrieved 2009-02-12.
    • Theresa Cedillo and Michael Cedillo, as parents and natural guardians of Michelle Cedillo vs. Secretary of Health and Human Services, 98-916V (United States Court of Federal Claims 2009-02-12).
  18. ^ Baker JP (February 2008). "Mercury, vaccines, and autism: one controversy, three histories". American Journal of Public Health. 98 (2): 244–53. doi:10.2105/AJPH.2007.113159. PMC 2376879. PMID 18172138.
  19. ^ "Thimerosal in Vaccines". Centers for Disease Control and Prevention. 2019-01-24. Retrieved 2019-02-07.
  20. ^ a b Offit PA (September 2007). "Thimerosal and vaccines--a cautionary tale". The New England Journal of Medicine. 357 (13): 1278–9. doi:10.1056/NEJMp078187. PMID 17898096.
  21. ^ "Vaccine Safety & Availability – Thimerosal in Vaccines". FDA. 5 April 2019.
  22. ^ Bose-O'Reilly S, McCarty KM, Steckling N, Lettmeier B (September 2010). "Mercury exposure and children's health". Current Problems in Pediatric and Adolescent Health Care. 40 (8): 186–215. doi:10.1016/j.cppeds.2010.07.002. PMC 3096006. PMID 20816346.
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  24. ^ "Vaccine Safety & Availability - Thimerosal in Vaccines". www.fda.gov. Retrieved 2016-02-08.
  25. ^ Sugarman SD (September 2007). "Cases in vaccine court--legal battles over vaccines and autism". The New England Journal of Medicine. 357 (13): 1275–7. doi:10.1056/NEJMp078168. PMID 17898095.
  26. ^ "UPDATE 1-US court rules again against vaccine-autism claims". Reuters. 2010-03-12. Retrieved 2019-02-07.
  27. ^ Salzberg, Steven. "Vaccine Court Ruling: Thimerosal Does Not Cause Autism". Retrieved 2019-02-07.
  28. ^ Dyer, Clare (2010-03-16). "Thiomersal does not cause autism, US court finds". BMJ. 340. pp. c1518. doi:10.1136/bmj.c1518. ISSN 0959-8138. PMID 20233774. Retrieved 2019-02-07.
  29. ^ Hilton S, Petticrew M, Hunt K (May 2006). "'Combined vaccines are like a sudden onslaught to the body's immune system': parental concerns about vaccine 'overload' and 'immune-vulnerability'". Vaccine. 24 (20): 4321–7. doi:10.1016/j.vaccine.2006.03.003. PMID 16581162.
  30. ^ Immune challenges:
  31. ^ Vaccine burden:
  32. ^ Nerd, Gid M.-K; Health (2017-12-05). "Vaccines Don't Cause Autism". Retrieved 2019-02-07.
  33. ^ Lidsky TI (May 2014). "Is the Aluminum Hypothesis dead?". Journal of Occupational and Environmental Medicine. 56 (5 Suppl): S73-9. doi:10.1097/JOM.0000000000000063. PMC 4131942. PMID 24806729.
  34. ^ Principi, N; Esposito, S (September 2018). "Aluminum in vaccines: Does it create a safety problem?". Vaccine. 36 (39): 5825–31. doi:10.1016/j.vaccine.2018.08.036. PMID 30139653.
  35. ^ "Vaccines, Autism, and Retraction". 2017-05-10. Retrieved 2019-02-07.
  36. ^ "Vaccine Study: Autism Link Ripped by Scientists". 2017-11-06. Retrieved 2019-02-07.
  37. ^ "Dwoskin Foundation – Science-Based Medicine". Retrieved 2019-02-07.
  38. ^ "UBC stands behind vaccine studies discredited by WHO". 2015-03-04. Retrieved 2019-02-07.
  39. ^ a b "Kristin Cavallari Defends Anti-Vaccine Stance". The Huffington Post. 19 March 2014. Retrieved 2016-02-08.
  40. ^ "Robert De Niro defends discredited idea linking vaccines to autism". Stat. 13 April 2016. Retrieved 2016-04-13.
  41. ^ Kluger J. "Jim Carrey, Please Shut Up About Vaccines". TIME.com. Retrieved 2016-02-08.
  42. ^ Tenbarge, Kat. "Bill Maher agreed with a controversial doctor, repeating a debunked theory that it was 'realistic' that vaccines have caused autism in children". Insider. Retrieved 2019-11-02.
  43. ^ "RFK Jr. Joins the Ranks of the Anti-vaccine Scaremongers". TIME.com. Retrieved 2016-02-08.
  44. ^ Hyman M, Herbert MR (2014-08-04). Kennedy RF (ed.). Thimerosal: Let the Science Speak: The Evidence Supporting the Immediate Removal of Mercury--a Known Neurotoxin--from Vaccines. Skyhorse Publishing. ISBN 9781632206015.
  45. ^ "Jenny McCarthy: "We're Not An Anti-Vaccine Movement ... We're Pro-Safe Vaccine"". FRONTLINE. Retrieved 2016-02-08.
  46. ^ Kluger J (2009-04-01). "Jenny McCarthy on Autism and Vaccines". Time. ISSN 0040-781X. Retrieved 2016-02-08.
  47. ^ "About Generation Rescue » Generation Rescue | Jenny McCarthy's Autism Organization". www.generationrescue.org. Retrieved 2016-02-08.
  48. ^ "Experts condemn Donald Trump for remarks on vaccines, autism". NY Daily News. Retrieved 2016-02-08.