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Opinions : MMR VACCINE & AUTISM – NO CAUSAL ASSOCIATION

Dr. Musa Mohd. Nordin
MBBCh (Wales) MRCP (UK) FRCP (Edinburgh) FAMM
Consultant Paediatrician & Neonatologist

To date there is no convincing evidence that any vaccine can cause autism or any kind of behavioral disorder.

The only evidence that has been presented to suggest this association was published in the Lancet ( Wakefield et al 1998). The Wakefield paper which is the centre of the current MMR ( Measles, Mumps, Rubella vaccine ) controversy was not evidence based. This study was reviewed by an expert committee from the UK MRC (Medical Research Council) which concluded "there is no evidence to link the MMR vaccine with autism".

Based on data from 12 patients, they suggested that MMR caused bowel problems leading to decreased absorption of essential vitamins and nutrients which resulted in autism. No scientific analyses were presented to substantiate their claims and furthermore factors such as referral bias and small sample size were not considered. And the claim of autism in the 12 patients was not supported by the author's own clinical data - at least 4 of the patient's had behavioural problems prior to the onset of symptoms of inflammatory bowel disease.

A later publication from the Wakefield group showed that patients with inflammatory bowel disease were negative for measles virus, indicating that measles is not responsible for inflammatory bowel disease.

In summary, the Wakefield paper is a very unscientific paper in the age of evidence based medicine but it has inflicted serious damages to the success story of immunisation. Children have benefited from vaccines more than any other medical preventative program in history ( well, maybe with the exception of the purification of water ). A retraction has been issued by 10 of the 12 authors of this highly controversial paper. And the Lancet editor Dr. Richard Horton issued an apology for publishing the study.

On the other hand, much scientific data exist to show no causal relationship between MMR ( or any other vaccines for that matter ) and autism. Taylor in the Lancet 1999, gave population based evidence of no link. Gillberg et al ( 1998 ) in Sweden studied two paediatric population and also found no evidence of an association between MMR and autism. In the US, which probably has the biggest adverse reactions databank, only 15 cases of autistic like behaviour were reported between 1990 - 1998. Due to the small numbers over a 9 year period, the cases are likely to represent unrelated chance occurrences that happened around the time of vaccination.

The US and Finland are virtually measles free with the successful 2 dose MMR regimen ( all the reported cases of measles were imported ). Measles is probably the next serious childhood disease to be eradicated following smallpox and polio.But with bad press and a gullible layperson, it is going to be a very tough, uphill battle for any public health immunisation drive.

What happened to children in Japan in the late 1970s should teach us all a painful lesson. In 1975, in response to negative publicity on the whooping cough vaccine, the Japanese Ministry of Health and Welfare imposed a moratorium on its use. In the three years following the moratorium, there were 13,000 cases of whooping cough and 113 associated deaths compared to 400 cases and 10 associated deaths prior to the moratorium.

Similarly in the UK, a hyped vaccine scare related to pertussis led to a rapid fall in immunisation uptake in the 1970s. An epidemic of pertussis resulted with more than 100,000 cases and 36 deaths.

We should not allow sensationalised unproven vaccine scares to cloud the science of evidence based vaccinology.