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Report of the MMR Expert Group

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Report of the MMR Expert Group

1 Introduction

Each chapter begins with a box containing a short description of its content, and ends with a summary of key points.

This chapter describes:

  • why the Expert Group was established and what it was asked to do (paragraphs 1.1 to 1.10);

  • how the members of the Expert Group were appointed (paragraphs 1.11 to 1.16 and Annex A); and

  • how the work of the Expert Group was taken forward in an open and inclusive way, and the individuals and organisations that contributed (paragraphs 1.17 to 1.33).

Background and Remit

1.1 Combined measles, mumps and rubella (MMR) vaccines were introduced into the UK routine childhood immunisation programme I in 1988. Initially, only one MMR dose was given, but a two-dose immunisation schedule with measles, mumps and rubella vaccine has existed in the UK since October 1996 (the first dose is given at 12-15 months and the second dose at 3-5 years).

1.2 Since 1998, however, there have been speculation and controversy surrounding the MMR vaccination focusing on a possible connection to inflammatory bowel disease and autism. This emerged as a result of the work of the Inflammatory Bowel Disease Study Group at the Royal Free Hospital and School of Medicine. In the early 1990s, they first suggested that the measles virus may be present in the bowel of individuals with inflammatory bowel disease. This work proved controversial as the findings could not be replicated in the peer-reviewed literature by others in the field. In 1998, the group published a paper describing 12 children with autism and an apparent novel form of bowel disease, and in eight of the children the onset of behavioural problems was linked to the time when MMR was administered. A press conference, held at the time of publication of this paper, created adverse publicity for the MMR vaccine.

1.3 Subsequent epidemiological studies of large numbers of children with autism have not found evidence of a link with MMR 1. Similarly, reviews of both autism and MMR have not supported the assertion that MMR is in some way a trigger for autism or inflammatory bowel disease 2.

1.4 Despite these studies, the public and media reaction has been somewhat different. Some 3000 parents who believe that their children have been damaged by the MMR vaccine are pursuing a legal action against the manufacturers. And, over time, a minority of parents in Scotland, and elsewhere in the UK, has decided to reject or postpone MMR immunisation, leaving their children, and others, at greater risk of contracting measles, mumps or rubella. This is illustrated below.

graph

(provided by SCIEH, using figures provided by ISD (Scotland) and PHLS CDSC (England, Wales and Northern Ireland)

1.5 In March 2000, the Public Petitions Committee considered Petition PE 145 by Mr Bill Welsh, which called for the Scottish Parliament to take a range of actions with regard to medical conditions arising from immunisations, against the background of that controversy and continuing concern about the public health implications. The petition was passed to the Health and Community Care Committee for further consideration.

1.6 The Health and Community Care Committee's 8th Report 3 stated that:

"on the basis of currently available evidence, there is no proven scientific link between the measles, mumps and rubella vaccine and autism or Crohn's disease and therefore the Committee has no reason to doubt the safety of the MMR vaccine. The Committee does not recommend any change in the current immunisation programme at this time".

The Committee also suggested that an Expert Group should be established to consider a range of questions relating to the concerns voiced by parents.

1.7 In its formal response 4 the Scottish Executive agreed to establish an Expert Group "to consider the matters raised by the Health and Community Care Committee relating to immunisation against measles, mumps and rubella, with particular reference to:

a) describing the consequences of pursuing an alternative vaccination policy to MMR;
b) reviewing evidence on the apparent rise in the incidence of autism, taking account of the current work of the Medical Research Council;
c) describing the process of vaccine testing and the monitoring of adverse effects; and
d) in all its work, having regard to the role and remit of the Joint Committee on Vaccination and Immunisation, the Committee on Safety of Medicines and the Medicines Control Agency".

1.8 The "matters raised by the Health and Community Care Committee" are largely defined by a series of questions posed by the Committee, which broadly underpin the formal remit of the Expert Group. The questions, and appropriate answers, are set out in Chapter 6.

1.9 It is, however, important to recognise that the remit of the Expert Group acknowledges both that other existing bodies advise Ministers on medicines, and immunisation policy, and that the Group would consider those matters, to some degree, in the course of its work.

1.10 Equally, it is worth acknowledging the shifting context for the Expert Group's work following the news of measles outbreaks in parts of England and in Scotland, early in 2002. The Public Health Laboratory Service has confirmed 95 cases of measles, with the majority (73) occurring in London. In Scotland, the Scottish Centre for Infection and Environmental Health (SCIEH) confirmed three cases of measles in Fife in March 2002 - the first such cases for 2 years.

Membership

1.11 The HCCC report stated that "membership of the group will be decided by the Scottish Executive but should include representatives from the Scottish Society for Autism".

1.12 The Executive's response of 29 June confirmed that the Chairman of the Expert Group would be The Very Revd Graham Forbes, Provost of St Mary's Cathedral, Edinburgh.

1.13 The Executive then consulted the Chairman, and a range of professional and voluntary bodies, including in particular the Scottish Society for Autism, about the selection of additional members. The Executive also had regard to Guidelines 2000: Scientific Advice And Policy Making5, which states that:

"Departments should draw on a sufficiently wide range of the best expert sources, both within and outside Government. These might include not only eminent individuals, learned societies, advisory committees, or consultants, but also professional bodies, public sector research establishments, lay members of advisory groups, consumer groups and other stakeholder bodies. As all experts will come to issues with views shaped to some extent by their own interests and experience, departments should also consider how to avoid unconscious bias, by ensuring that there is a good balance in terms of the type of institutions and organisations from which the experts are sought. Experts from other disciplines, not necessarily scientific, should also be invited to contribute, to ensure that the evidence is subjected to a sufficiently questioning review from a wide-ranging set of viewpoints.

Departments should ask prospective experts to follow the seven principles of public life as set out by the Committee on Standards in Public Life, which include the obligation to declare any private interests relating to their public duties. Departments should judge whether these interests could undermine the credibility or independence of the advice.

Where departments conclude that the potential conflicts of interest are not likely to undermine the credibility or independence of the advice, the relevant declarations of interests should, as a minimum, be made available to anyone who is proposing to act in reliance upon the advice. Departments will also need to consider whether it is appropriate to make the declarations more widely available."

1.14 Consistent with that, and the HCCC report, Mrs Jane Hook, Dr Clare Brogan and Mrs Gillian Hamer-Hodges were appointed to represent the interests, expertise and membership of the Scottish Society for Autism, the National Autistic Society, and the National Association for Colitis and Crohn's Disease, respectively. Details of the full membership of the Group were announced on 28 August 2001, the date of the first meeting.

1.15 The members of the Expert Group subsequently expressed a wish to broaden the membership in order to extend further their knowledge and understanding of matters relating to the diagnosis of autistic spectrum disorders, and the related provision of care. As a result, the Executive invited Dr Kenneth Aitken and Dr Gordon Bell to join the Expert Group, in a personal capacity, and they participated fully from November 2001.

1.16 The complete list of members and a separate summary of declared interests are at Annex 1.

Timetable and Process

1.17 The Expert Group met for the first time on 28 August 2001, and on eight subsequent occasions to consider relevant evidence and prepare this report.

1.18 A number of individuals and organisations provided oral and written submissions at those meetings:

The Medicines Control Agency
Ms J Muirie, The Public Health Institute of Scotland
The Medical Research Council
Mr A J Wakefield (formerly Royal Free and University College Medical School)
Action Against Autism (Mr W Welsh, accompanied and assisted by Mr D Thrower,
Dr P Copp and Dr K Aitken)
Dr S Davies, Borders NHS Health Board
Scottish Centre for Infection and Environmental Health and the University of Strathclyde (Dr C Bramley and Mr Peterson)
Ms J E Baines, Highland Region Education Department
Professor C Gillberg, University of Gothenburg
Dr D A C Elliman, St George's Hospital, London
Professor J Satsangi, University of Edinburgh.

Consultation

1.19 In week commencing 17 September 2001, adverts were placed in the Health Service Journal, Aberdeen Press & Journal, The Scotsman, The Herald and Daily Record. The adverts gave the full remit of the Expert Group and invited relevant contributions from individuals and organisations.

1.20 In response to that consultation process written submissions were provided by:

Faculty of Public Health Medicine
Royal College of General Practitioners
Royal College of Nursing - Scottish Board
Royal College of Physicians
Royal College of Physicians of Edinburgh
Royal College of Paediatrics and Child Health - Scottish Committee
Royal College of Physicians and Surgeons Glasgow
Royal College of General Practitioners (Scotland)
Renfrewshire Autism and Asperger Group
Sense Scotland
Dr N Waugh
Mr R Miles
Mr D Thrower
Mrs S Campbell
Ms D Taylor
Dr A Clegg
Mr V Arcari
Ms A Laverty
Ms Y Gowans
Mr B Barreto.

1.21 The Expert Group gratefully acknowledges the support and assistance of all those individuals and organisations who contributed. Full details of their submissions II are available on http://www.show.scot.nhs.uk/mmrexpertgroup/.

Parents' Reference Group

1.22 As part of that process of consultation, the Expert Group established a broadly representative Parents' Reference Group to both inform its deliberations (by identifying priority issues relevant to its remit) and provide constructive comment on emerging conclusions.

1.23 Scottish Health Feedback (SHF), an independent research organisation which has been involved in several studies looking at parents' and health professionals' opinions about immunisation in general, and MMR in particular, managed this element of the work. SHF identified parents who might wish to be included in the Reference Group and worked with them to assess their priorities in relation to MMR and their views on the value of an earlier draft of this report. Full details of the contribution made by the Parents' Reference Group are set out in the reports prepared by Scottish Health Feedback. The reports are available on http://www.show.scot.nhs.uk/mmrexpertgroup/.

1.24 The Expert Group gratefully acknowledges the very valuable contribution of the Parents' Reference Group.

1.25 Taking account of the views of the Parents' Reference Group in particular, and others including the Health and Community Care Committee, this report seeks to either provide, or highlight the availability of, good, clear and concise information about autism, about MMR and about single vaccines. In this context, the Expert Group acknowledges that the MMR discussion pack6, produced in 2001 by the Scottish Executive, the Scottish Centre for Infection and Environmental Health, and the Health Education Board for Scotland, sets out some facts about MMR in a way that helps health professionals and parents to explore any concerns together.

Evaluation of evidence

1.26 The Expert Group acknowledges that the process of evaluating evidence for the causation of disease is not easy. Although not formally tasked with doing this, the Expert Group was very aware that the background to its remit included concerns about the relationship between MMR, autism and bowel disease.

1.27 The Expert Group received submissions that addressed the issue of associations between these three. However, association is not causation, and it acknowledged the likely contribution of both genetic and environmental factors to the causation of autism and bowel disease, and the interaction within and between them. The question of definitions and the possibility of multiple causes were also acknowledged and are discussed below.

1.28 To determine the cause(s) of a disease or syndrome, certain scientific criteria must be satisfied, and the processes of evaluation of evidence observed. To evaluate biomedical (scientific) evidence both inductive and deductive methods are customarily used. The inductive method involves the amassing of evidence to support a prior hypothesis, while the deductive method tests a hypothesis by trying to falsify it. Generally the latter is regarded as a more powerful and secure route to scientific certainty, but both require systematic unbiased collection of information, through observation and experiment, in different populations and using a variety of appropriate study designs, in order to elucidate the relationship between proposed causes and the conditions in question.

1.29 In the evaluation of evidence there is a hierarchy of study designs or "statements of evidence" available to the investigator, ranging from the meta-analysis of randomised controlled trials, through experimental studies to case series. Evidence obtained from "expert" committee reports or opinions and/or clinical experience of "respected authorities" is regarded as the weakest source of evidence in this hierarchy 7.

1.30 The Expert Group was greatly assisted by the MRC Review of Autism Research (2001) 8, which was published during the course of its deliberations. The section (paragraphs 84 to 88) on "Criteria to Assess Causality" deals in some detail with the processes and difficulties in identifying possible causative relations between MMR, autism and bowel disease.

1.31 The Expert Group received verbal and written submissions which sought to both support and refute causative relations between MMR, autism and bowel disease. Much of this has been reviewed by the MRC, and some is discussed in Chapter 2 of this report.

Other matters

1.32 In the course of addressing its remit and considering the submissions presented by others, the Expert Group has, on occasion, reflected on the fact that it is not a scientific expert group in a conventional sense, because its members have a broader range of experience and expertise. This recognises the many different facets of the remit. The Expert Group considers that this inclusive and multidisciplinary approach has enabled an holistic, searching and coherent examination of the issues.

1.33 The HCCC report stated that "it is important to view this Report as the beginning of a process of investigation and clarification of all the issues and strategies surrounding the combined vaccine, rather than as a definitive set of conclusions". The Expert Group agrees that its own report should also be viewed as a stage in an ongoing process, particularly in relation to the causes and treatment of ASD.

Chapter 1 - Summary of Key Points

This report sets out the views of the Expert Group established "to consider the matters raised by the Health and Community Care Committee (HCCC) relating to immunisation against measles, mumps and rubella, with particular reference to:

  • describing the consequences of pursuing an alternative vaccination policy to MMR;

  • reviewing evidence on the apparent rise in the incidence of autism, taking account of the current work of the Medical Research Council (MRC);

  • describing the process of vaccine testing and the monitoring of adverse effects; and

  • in all its work, having regard to the role and remit of the Joint Committee on Vaccination and Immunisation, the Committee on Safety of Medicines and the Medicines Control Agency".

The remit makes clear that other bodies advise Ministers on medicines, and immunisation policy.

The Expert Group was determined to complete that task in an open and inclusive way, and to undertake a thorough, questioning review from a wide-ranging set of viewpoints. It gratefully acknowledges the support and assistance of all those individuals and organisations who contributed to this work, particularly the Parents' Reference Group.

Details of the members and their declared interests (also at Annex 1), the consultation process adopted, and the submissions from individuals and organisations are available onhttp://www.show.scot.nhs.uk/mmrexpertgroup/.

The Expert Group believes that this report should be viewed as a stage in an ongoing process, particularly in relation to the causes and treatment of ASD.