1 The MMR controversy
The furore over the measles, mumps and rubella (MMR) vaccination has rapidly escalated into a landmark controversy in the UK. Since the suggestion in 1998 by Dr Andrew Wakefield that MMR might be implicated as a cause of autism, a steady stream of claim and counterclaim has been played out in the scientific press, and newspaper headlines have see-sawed between condemnation and commendation (see the chronicle of events outlined in Box 1). More generally, the MMR debate illustrates that public health programmes are frequently underpinned by a strong ‘reliance on science’, which may not be an effective persuasive strategy for its target audience. Instead, this course will show that the public have witnessed an element of dissent within the scientific and medical establishments. Furthermore, the political and scientific management of this conflict, and a reluctance to acknowledge the social context within which it has arisen, have given the debate a longevity and potency perhaps far beyond that which the scientific arguments themselves warrant.
MMR vaccine consists of a freeze-dried preparation of live but weakened (attenuated) virus particles, intended to provoke recognition of the measles, mumps and rubella viruses by the body's immune system but not cause any symptoms of the diseases themselves. The vaccine is usually given in two doses, both by injection. The first dose is given to babies aged 12–15 months, and the second (a ‘booster’) is given at school age, intended to protect those children (about 5–10%) that did not respond to the first dose. The triple vaccination programme was introduced in the UK in 1988. It replaced the single vaccine given to babies for measles and a vaccination for rubella given to teenage girls. Mumps was not previously widely vaccinated against.
Autism, the condition implicated in the furore, is a distressing and debilitating developmental disorder in which sufferers have poor social interaction, impaired imagination and difficulty communicating. It encompasses a spectrum of conditions which range in severity. Leo Kanner first coined the phrase ‘autism’ (from the Greek autos for ‘self’) in 1943. Until the 1990s autism was thought to be very rare, affecting 2–4 children per 10 000. Since then, the rate has risen to an estimated 60 per 10 000. It is not certain what has caused this rise, although increased awareness and changes in diagnostic criteria are thought to account for most of it (Wing and Potter, 2002).
In spite of intensive research, considerable uncertainty surrounds the causes of autism. Studies using twins suggest that genetic factors have a major role in most cases. Ten times as many boys are affected as girls, implicating a genetic link to the sex chromosomes. If the recent rapid increase in rates of autism is genuine rather than an artefact of increased diagnosis, environmental factors are likely to be involved. Various causes for autism have been suggested in the scientific literature, such as diet, pollutants, antibiotics, allergies, vaccines, neurotoxins and foetal hormone levels. Although none of these factors has been scientifically validated to date, neither have they been categorically ruled out as contributing to autism. One thing is clear however: there is no incontrovertible evidence to date to support a causative link between the MMR vaccine and autism.
In this course, we'll explore why the MMR controversy has loomed so large in public consciousness. We'll have a look at the effects of media coverage, and see how social factors are inextricable from science when it comes to assessing risk. Like many other parents of young children, I have had to take a difficult decision about whether or not to trust the MMR vaccine. The scientific consensus is almost unanimous against an association between MMR and autism, so why do parents agonise about it? Is this a symptom of wider public anxiety about scientific pronouncements on public health, and is this uneasiness justified?
Box 1 Chronicle of some of the main events in the MMR controversy
|October 1988||The MMR vaccine replaces single vaccines for measles and rubella in the UK.|
|April 1993||Andrew Wakefield claims to have established a link between measles and Crohn's disease (an intestinal disorder), but further studies could not confirm this.|
|28 February 1998||Wakefield and 12 co-authors publish an early report in The Lancet showing intestinal inflammation in 12 children with developmental disorders. Wakefield announces his concern about links between MMR and autism at a press conference.|
|23 March 1998||Meeting of 37 experts by Medical Research Council reviews published and unpublished evidence and concludes there is no link between MMR and autism.|
|2 May 1998||Finnish study published in which reported adverse reactions to the MMR vaccine between 1988 and 1996 revealed no association between MMR and autism.|
|12 June 1999||Epidemiological study of 498 cases of autism in eight North Thames health districts finds that there was no sudden step-up increase in diagnoses after the introduction of MMR in 1998 and no developmental regression clustered after vaccination.|
|6 April 2000||Wakefield testifies in support of his MMR–autism hypothesis to a US Congressional Hearing.|
|December 2000||Wakefield publishes a paper entitled ‘MMR vaccine: through a glass, darkly’, criticising safety procedures when MMR was first introduced.|
|21 January 2001||Wakefield discloses to the Telegraph that he has seen 170 cases of ‘a new syndrome of autism’, with the majority of cases backed by documentary evidence of regression following vaccination. He claims that regulators have failed to adequately address safety of the MMR vaccine.|
|March 2001||Department of Health drops advertising campaign to promote MMR in the face of criticism that the money would be better spent on research into autism.|
|9 June 2001||Lothian division of the British Medical Association (BMA) requests the BMA to back single vaccines as an alternative for parents who refuse the MMR.|
|30 November 2001||Wakefield ‘asked to resign’ from Royal Free Hospital.|
|13 December 2001||Review by Medical Research Council into autism finds that the number of cases has increased (6 in 1000 children), but this is largely due to increased recognition and changing definitions of autism. The report finds no evidence of a link with MMR.|
|19 December 2001||During Prime Minister's Questions, MP Julie Kirkbride asks Mr Blair whether his son Leo had been immunised with MMR. Mr Blair declines to answer on privacy grounds.|
|3 February 2002||BBC TV Panorama special presents a largely sympathetic account of Wakefield's hypothesis. Wakefield claims that research has found measles in the guts of 75 of 91 autistic children with bowel disease.|
|19 June 2002||Wakefield presents evidence to a US congressional committee claiming that the measles virus identified in the guts of autistic children had been identified by a team led by John O'Leary as originating from the vaccine. The technique was subsequently criticised as being too crude to discriminate wild infection from the vaccine.|
|2 July 2002||Ken Livingstone, Mayor of London, announces that he will opt for single vaccines for his as yet unborn child.|
|7 November 2002||Danish study of half a million infants finds that autism is no more prevalent in vaccinated vs unvaccinated children.|
|13 June 2003||High Court rules that children of two estranged couples should have the MMR vaccine, against the mothers' wishes.|
|27 February 2004||Parents who believe their children were damaged by MMR are refused legal aid funding to sue manufacturers of the vaccine.|
|6 March 2004||Ten of the 13 authors of the original Lancet paper issue a partial retraction.|