The MMR Vaccine and Autism

Transcription

1 The MMR Vaccine and Autism

2 Autism overview and prevalence MMR vaccine History of concerns Wakefield s study linking MMR and autism Reaction to Wakefield s study Brian Deer s investigation Aftermath of investigation The role of pharmaceutical companies Allegations against Brian Deer The current state of things New research on causes of autism Implications for studying controversy

3 Neurodevelopmental condition involving: Reduced social interaction / communication Restricted and repetitive interests or behaviours Difficulty with change Atypical eating Symptoms can develop gradually or more suddenly with regression Onset is before age 3 Boys are 5X more likely to develop autism than girls Diagnosis is behavioural, not biological Currently no known cure There is much scientific uncertainty about its cause(s)

4 Autism Rate 1.40% 1.20% 1.00% 0.80% 0.60% 0.40% 0.20% 0.00% Possible explanations Changing diagnostics GM food Mercury in vaccines MMR vaccine

5 Introduced in North America in 1971 Combination of attenuated measles, mumps and rubella viruses Recommended for children months Second shot at 4-6 years Known side effects Common: fever, mild rash, swelling of facial / neck glands Uncommon: febrileinduced seizure Very Rare: severe allergic reaction, coma, brain damage

6 1980s: parents start observing disorders in their children shortly after MMR vaccination Meningitis, brain inflammation, seizures, autism Bowel disorders 1980s-1990s: parents begin suing MMR vaccine manufacturers for damages Several cases resulted in compensation to parents Correlational or causal association?

7 1998: study by Wakefield and others published in the Lancet Studied 12 children, 3-10 years of age diagnosed with autism and bowel disorders In 8/12 cases symptoms appeared about 6 days after MMR vaccination Theory: MMR vaccine damages gut Brain exposed to harmful metabolites Autism

8 Not a very strong study Non-random, uncontrolled clinical case study Suggested the connection between autism and the bowel disorders was causal, but that we did not prove an association between measles, mumps, and rubella vaccine and the syndrome described (p.641) But Wakefield recommended avoidance of MMR vaccine in favour of single vaccines No evidence single vaccines were safer

9 Media and anti-vaccination movement sensationalized results Played up link between MMR and autism Downplayed weaknesses in Wakefield s study Most follow-up studies fail to replicate results Health organizations / doctors: no evidence of link Not widely reported in the media MMR vaccination rates in across Western world drop noticeably Rates of measels, mumps and rubella begin to rise

10 Wakefield was being paid by lawyers for an MMR lawsuit Most study participants involved in the lawsuit Wakefield ignored data that didn t support his theory 1997: Wakefield filed for a patent for a stand-alone measles vaccine Accused Wakefield of fabricating / changing data to suit theory Suggested conspiracy to manufacture vaccine scare to profit from new vaccine and autistic enterocolitis diagnostic kits

11 : The General Medical Council investigation Wakefield did not have approval for invasive procedures on children in study Wakefield should have disclosed conflicts of interest Wakefield loses ability to practice medicine in UK 2010: The Lancet issues a full retraction of Wakefield s 1998 article 2011: British Medical Journal publishes series of articles by Deer highlighting evidence of Wakefield s fraud Media stories report on Wakefield s conflicts and fraud

12 MMR manufacturers face huge liabilities if a link to autism is accepted Many settlements have occurred for allegations of vaccine-caused illness (including autism) BMJ receives funding from Merck and GSK (makers of MMR) May have suppressed dissenting views on whether Wakefield committed fraud One of the members of the General Medical Council is a shareholder in GSK

13 Deer may have acted unethically in his investigation Interviewed families in Wakefield s study under false pretenses Published confidential information on children s case files in BMJ without permission Deer may have been supported by the makers of MMR: Deer s employer, The Sunday Times, is owned and managed by the Murdoch family who has significant stock in GSK Deer s article was written with help of Medico-Legal Investigations, an organization funded by the pharmaceutical industry BMJ paid Deer to write articles against Wakefield

14 MMR vaccination rates are still low 1 in 4 Americans believe that vaccines cause autism Government and medical doctors maintain safety of MMR Public health benefit outweighs individual risks of MMR Wakefield s research has been widely discredited by scientists and mainstream media Alternative health industry and anti-mmr groups maintain his innocence Deer is valourized by doctors and scientists Anti-vaccination, alternative news groups demonize him as unethical, mentally unstable and funded by big pharma Research on MMR and autism is ongoing

15 Emerging research suggests that imbalances in gastro-intestinal flora may be a contributing factor in autism 70 per cent of kids with autism also have severe gastrointestinal symptoms Theory: Bacterial imbalance damages gut Brain exposed to harmful metabolites Autism

16 1. The popularity of an idea is not necessarily related to its accuracy or trustworthiness 2. Media information is often sensationalist, inaccurate, incomplete or biased 3. Debate among scientists is the norm 4. Peer-reviewed scientific studies cannot be assumed to be credible and scientists are not always trustworthy 5. No group involved in the MMR autism controversy is completely trustworthy Wakefield, anti-vaccine groups, parents, doctors, pharmaceutical companies, Brian Deer, media, peer-reviewed scientific journals