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Report of the MMR Expert Group

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Report of the MMR Expert Group

5 The Consequences of Alternative Vaccination Policies

This chapter describes:

  • the risks associated with measles, mumps and rubella (paragraphs 5.2 to 5.7);

  • the purpose of vaccination, both generally and in relation to measles, mumps and rubella (paragraphs 5.8 to 5.12);

  • the immunisation policy in place in Scotland and the UK, and elsewhere in Europe (paragraphs 5.13 to 5.25);

  • a framework of principles for immunisation policy (paragraph 5.26 to 5.31); and

  • the possible consequences of alternative vaccination policies (paragraphs 5.32 to 5.52).

Introduction

5.1 As indicated in paragraph 1.7, the Expert Group was asked by the Executive to describe the consequences of pursuing an alternative vaccination policy to MMR, and as such recognised that it was not expected or required to review MMR policy or the current immunisation programme. The Group also acknowledged that the Health and Community Care Committee's 8th Report stated that:

"The Committee believes that on the basis of currently available evidence, there is no proven scientific link between the measles, mumps and rubella (MMR) 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."

Other "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 answers are set out in Chapter 6.

Risks Associated with Measles, Mumps and Rubella

5.2 The success of immunisation against measles, mumps and rubella has led to a decline in the incidence of these diseases. As a result, the serious risks 6 associated with measles, mumps and rubella infection may not be fully appreciated:

Complications of measles

Complications of mumps

Complications of rubella

  • ear infection (1 in 20)

  • pneumonia/bronchitis (1 in 25)

  • convulsions (1 in 200)

  • diarrhoea (1 in 6)

  • meningitis/encephalitis (1 in 1000)

  • conditions affecting blood clotting (1 in 6000)

  • late onset subacute sclerosing panencephalitis (SSPE) (1 in 8000 children under 2 years)

  • deaths (1-2 deaths in 1000 reported cases in recent years)

  • viral meningitis (1 in 20)

  • encephalitis (1 in 1000)

  • permanent hearing loss (1 in 20,000)

  • inflammation of testicles (4 in 10 adult males)

  • inflammation of ovaries

  • encephalitis (1 in 6000)

  • birth defects (90% chance baby will have birth defects if mother catches rubella early in pregnancy). Birth defects include blindness, deafness, learning difficulties and heart disease

  • conditions affecting blood clotting (1 in 3000)

5.3 Serious complications have been reported for one in 15 notified cases of measles 51, but are more common and severe in chronically ill children 52. A particularly distressing complication is subacute sclerosing panencephalitis (SSPE). This is a rare degenerative neurological condition that can develop some years after natural measles infection to cause gradual loss of function and death within a few years 53. The risk is greatest in those who were infected at a young age. The graph below shows that the incidence of SSPE has decreased with the reduction in measles. Case fatality rates for measles infection, in general, are age related, and so rates vary depending on the age at infection. However, in recent years, one to two people in every 1000 with reported measles infection have died from it 54.

graph

Source: PHLS-CDSC

5.4 Death from measles is highest in children under one year - a group that do not receive MMR vaccine - and in those who are immunosuppressed, due to disease (e.g. leukaemia) or treatment (e.g. organ transplantation) and cannot receive MMR vaccine (or indeed single vaccines). In children receiving immunosuppressive treatment, e.g. for leukaemia or after organ transplantation, measles was a major cause of morbidity and mortality. Between 1970 and 1983, 19 children with acute lymphatic leukaemia died from measles in England and Wales 54. A study conducted at four UK hospitals between 1974 and 1984 identified 3 cases of measles encephalitis and two cases of measles pneumonia in children with acute lymphoblastic leukaemia at the Royal Hospitals for Sick Children in Glasgow and Edinburgh.

5.5 There have been several recent measles outbreaks in Northern Europe. In The Netherlands, there were 2961 notifications of measles in the period April 1999 to January 2000 55. Serious complications were reported in 17% of cases, with 2.2% (68) requiring hospitalisation. There were three deaths. The most prevalent complications were pneumonia (193) and otitis media (196). The majority of cases (77%) occurred in the 1-9 year age group. The Republic of Ireland had an outbreak of measles in 2000, with over 1600 cases 56. There were over 110 hospital admissions and three deaths.

5.6 Mumps can have serious complications, with neurological involvement in 10-20% of cases 57. Before mmunisation, it was one of the main causes of acquired sensorineural deafness in childhood 58. Inflammation of the testes in males is perhaps the most well-known complication, particularly when infected as an adult 59. Approximately half of these cases may have some testicular atrophy, although reports of sterility are rare. Girls can get oophoritis (inflammation of the ovaries). Death is a rare outcome of mumps and is most often associated with mumps encephalitis. Again, there have been several recent mumps outbreaks in Europe: in Northern Ireland in 2001; in Switzerland in 1999; and in Spain and Portugal in 1998 and 1996 respectively.

5.7 Rubella is generally a mild illness, which, if acquired by mothers in early pregnancy, nevertheless can have devastating effects on unborn children 60. The virus affects all fetal organs and can lead to serious birth defects. These include learning difficulties, cataracts, deafness, cardiac abnormalities, retardation of uterine growth and inflammatory lesions of the brain, liver, lungs and bone marrow. Maternal rubella infection in the first 10 weeks of pregnancy results in fetal damage in up to 90% of infants and multiple defects are common. Rare, non-pregnancy related, complications of rubella are encephalitis and idiopathic thrombocytopenic purpura (ITP). In 1993 an epidemic of rubella in Greece was followed approximately 6-7 months later by an outbreak of congenital rubella. Twenty-five cases were recorded (24.6 per 100,000 live births). All had serious symptoms, and seven died within 12 months 61.

The Current Immunisation Policy

5.8 The stated strategic objectives of the immunisation programme as a whole are: prevention of diseases at the individual level; control of disease at the population level; and elimination or eradication of the disease.

5.9 Eradication is a feasible long-term objective. For example, the World Health Organisation has adopted a resolution calling for global eradication of polio by the end of 2005. Three WHO Regions have not identified a single case caused by wild poliovirus for over 2 years. In the European Region the last case was in Turkey in November 1998. The UK, along with other countries of the European Region, is moving rapidly towards the certification of poliovirus eradication.

5.10 Once poliovirus transmission has been interrupted globally, the only potential source of wild poliovirus infection will be laboratories. Polio eradication will not be complete until all potential sources of poliovirus, including laboratory sources, are identified and contained.

5.11 Few medical procedures or treatments can compare with the enormous benefits to humanity from immunisation, one of the safest and most cost-effective of interventions 62. However, no one claims that vaccines never have any side-effects. Vaccines can, very rarely, cause serious adverse effects. Such adverse effects are significantly more common following the natural disease. Immunisation programmes are in place all around the world precisely because, at both the individual and population levels, the benefits far outweigh any potential risk.

5.12 The Vaccine Damage Payments Act 1979 introduced a scheme of payments for those severely disabled as a result of vaccination. Where a person has been severely disabled as a result of vaccination, a tax-free one-off lump sum is payable (currently 100,000). This payment is not compensation, but is designed to ease the present and future burdens of those suffering from vaccine damage and their families. A payment under the scheme does not prejudice the right of the disabled person to pursue a claim for damages through the courts.

Prevention and control of measles, mumps and rubella

5.13 Prevention and control of measles, mumps and rubella are important elements of the routine childhood immunisation programme in most of the developed world. Annex 2 contains a snapshot of immunisation programmes in 17 European countries (the 15 EU Member States plus Norway and Switzerland), taken from the Scientific and Technical Evaluation of Vaccination Programmes in the European Union - known as the EUVAX Project Report. According to a questionnaire survey carried out by the EUVAC-NET in 2000, all countries in the EU have implemented a schedule of two doses of measles, mumps and rubella vaccine 63.

5.14 In Scotland, as elsewhere in the UK, two doses of the MMR vaccine are offered (at 12-15 months, and at 3-5 years), subject to the child having no medical contraindications and parental consent. This policy is based on independent medical and scientific advice to Health Ministers from the Joint Committee on Vaccination and Immunisation, and recognition that expert advice from around the world endorses MMR as the safest and most effective vaccine in order to protect all children from these very serious, and potentially fatal, diseases. There are of course some children who should not have MMR (see paragraphs 5.22 et seq). These children can only be protected by the fact that most others are vaccinated, and unlikely to be carrying these diseases.

5.15 The aim of vaccination in the individual is to produce long-lasting immunity so that, if a person is subsequently exposed to wild viruses, he or she is able to rapidly prevent the virus multiplying and thereby avoiding illness. If a mother has been vaccinated against measles, mumps or rubella or has experienced natural infection, her blood will contain antibodies designed to target and eliminate these specific viruses. During pregnancy, these antibodies enter the unborn child, but they usually decline between 6 and 12 months of age. If MMR vaccine is given when a baby's blood contains these antibodies, the vaccine will effectively be inactivated before the baby is able to mount its own long-lasting immune response. This is why the first dose of MMR is offered at 12-15 months. As such, children under 1 year old (and indeed unimmunised pregnant women) rely on population protection for their personal protection.

5.16 The rationale for administering a second MMR dose at 3-5 years is based on the fact that, on an individual level, MMR does not provide protection against measles in up to 10% of children who receive one dose. Furthermore, at present more than 10% of children do not receive that first dose of MMR. Both of these groups remain susceptible to measles after one dose of MMR vaccine has been offered. As such, on a community level, it is not possible to achieve population protection and effective disease control with a one-dose schedule. If approximately 90% of children receive MMR, and in 10% of these it fails to work, only 81% will be immune after one doses i.e. 19% unprotected. More than 90% of the population need to be immune for measles to be eliminated. If population protection is not achieved, breakthrough outbreaks will occur among non-recipients, non-responders, infants aged less than 1 year who are too young to be vaccinated and immunocompromised children in whom MMR is contraindicated. For these reasons, a two-dose schedule is recommended in the UK. A second MMR vaccination protects most children who do not respond to the first dose - around 90% will respond to the second dose. This reduces the chance of an individual remaining susceptible from 1 in 10 to 1 in 100 after a second dose. A further benefit is that it boosts the antibody levels of those children who did respond to the first dose. Finally, by offering a second dose of MMR vaccine, those children who did not receive a first dose get a second chance to be immunised. (The corresponding figure is approximately 10% for mumps and 5% for rubella, but the rationale is explained using the figures for measles only for the sake of simplicity). In summary, 99% of those vaccinated will be protected by two doses of MMR.

flow chart

5.17 MMR immunisation uptake rates are calculated and published quarterly, for quarters ending March, June, September and December, and annually. The cohorts used in the calculation of the uptake rates are based on all children reaching a specified age who were registered on the systems at the end of the reporting period. As such, quarterly figures to the end of December 2001 showed MMR uptake at 86.6% across Scotland. These figures relate to children who have reached age 2 during the period in question, although these children may have been immunised any time up to 15 months previously. The latest annual figures 64 are:

Year

Primary immunisation

Pre-school booster

2001

89%

88.3%

2000

93%

90%

MMR - serious adverse effects

5.18 Few medical procedures or treatments can compare with the enormous benefits to humanity from immunisation. It is one of the safest and most cost-effective of interventions. Very rarely, MMR can cause serious adverse effects. Such adverse effects are significantly more common following the natural disease as the following table 6 shows.

Conditions

Children affected after the natural disease

Children affected after the first dose of MMR

Febrile convulsions (temperature fits)

1 in 200

1 in 1000

Meningitis/encephalitis

1 in 1000 (measles, mumps encephalitis)
1 in 20 (mumps meningitis)
1 in 6000 (rubella encephalitis)

less than 1 in 1,000,000

Conditions affecting blood clotting (ITP)

1 in 3000 (rubella)
1 in 6000 (measles)

1 in 22,000

Severe allergic response (anaphylaxis)

-

1 in 100,000

SSPE (a delayed complication of measles that causes brain damage and death)

1 in 8000 (children under 2)

0

Deaths

1 in 2500 to 1 in 5000 (measles; higher in children under 1)
1-2 in 1000 for measles in recent years

0

5.19 Idiopathic thrombocytopenic purpura (ITP) is a condition that affects blood clotting due to a shortage of platelets in the blood. This causes the blood to clot less easily and can result in a purple rash on the patient's body as mild bleeding beneath the skin can occur. ITP often follows viral infection and most cases do not follow vaccination. ITP occurs much less frequently after MMR vaccination than it does after natural infection.

5.20 There is no increased risk from a second dose of MMR vaccine, with the exception of allergic reactions. If complications were to occur, they would most likely be in the 5-10% of children who did not respond to the first dose: the weakened virus is killed as soon as it enters the body of a child who is already immune. The overall risk of complications after a second dose of MMR vaccine is therefore 90-95% less than that after the first dose.

5.21 As with any medical procedure, health care professionals are obliged to explain the advantages and disadvantages of vaccination 65. The literature provided for parents and professionals describes all the known adverse effects of MMR. There are no other serious conditions for which there is evidence to indicate an increased risk after MMR immunisation. The Expert Group considers that the information provided to parents when they are invited to bring their child to be immunised should now be reviewed and regularly updated.

Children who should not have MMR

5.22 There are, of course, some children who should not have MMR (see box over), at all, or at a particular time.

5.23 As indicated above, in paragraph 5.3, measles can be a major cause of morbidity and mortality in children receiving immunosuppressive treatment, e.g. for leukaemia or after organ transplantation. In such circumstances, children are protected by the "population-immunity" that is a product of high immunisation uptake. Essentially, these children are protected by the fact that most other children are protected, and unlikely to be carrying the disease and infecting others.

5.24 In addition, as outlined in Chapter 4 (paragraph 4.26 et seq), existing legislation and policy allow a licensed importer to import a single measles or mumps vaccine and supply it in response to a doctor's prescription to meet the "special needs" of an individual patient, on the doctor's direct personal responsibility.

MMR CONTRAINDICATIONS (based on Immunisation Against Infectious Disease 1996 - The Green Book)

Absolute contraindications to MMR

  • Children with untreated cancer or diseases of the immune system, those receiving immunosuppressive therapy or high dose steroids. This includes:

    • all patients currently being treated for malignant disease with chemotherapy or generalised radiotherapy or within 6 months of terminating such treatment;

    • all patients who have received an organ transplant and are currently on immunosuppressive treatment;

    • patients who within the previous 6 months have received a bone marrow transplant;

    • individuals on lower doses of steroids in combination with cytotoxic drugs - specialist advice should be sought;

    • individuals on lower doses of steroids or other immunosuppressants for prolonged periods or who because of underlying disease may be immunosuppressed and are at increased risk of infection. Specialist advice should be sought;

    • patients with evidence of impaired cell mediated immunity, e.g. HIV infection with current symptoms and various immunodeficiency syndromes;

  • HIV positive individuals - specialist advice should be sought;

  • Children with allergies to neomycin or kanamycin;

  • Severe reaction to previous MMR.
    (Like other live vaccines, MMR should not be administered to pregnant women.)

Reasons to postpone MMR

  • Child is generally unwell with a fever;

  • If a child is suffering from an acute illness, immunisation should be postponed until recovery has occurred;

  • Child has had another live vaccine (including BCG) in the last 3 weeks;

  • Child has been given an injection of immunoglobin in the last 3 months.

Not contraindications

  • Egg allergy. Although tissue derived from eggs is used to grow the vaccine virus, as much as possible is removed. A number of scientific papers have been published which demonstrate the safety of MMR vaccine, even in children with a known severe egg allergy. MMR vaccine can be administered in hospital to children with a history of anaphylaxis to eggs, if there is particular parental concern;

  • Previous history of measles;

  • Minor infections without fever or systemic upset.

5.25 The Expert Group recognises that some health professionals and some parents of children with IBD and/or ASD have particular concerns about immunising children with IBD and/or ASD and their siblings. The Group recommends that CSM and JCVI should, taking account of ongoing and future research into the causes of IBD and ASD, continue to keep these vaccination contraindications under review.

A Framework of Principles for Immunisation Policy

5.26 The Group accepted and endorsed, without reservation the high-level strategic objectives of immunisation:

  • prevention of disease at the individual level;

  • control of disease at the population level; and

  • elimination or eradication of disease.

But it considered that a broader range of explicit principles should underpin immunisation policy, albeit that some will have greater priority than others at any given point in time.

5.27 In the course of discussing these issues, the Expert Group developed the following framework of principles for the public/childhood immunisation programme in order to guide its thinking:

A. A rigorous evidence-based and transparent process should validate the safety, quality and efficacy of vaccines that are offered within the programme, in order to provide treatment and care which represent best scientific and clinical practice. Scientific data about the safety, efficacy, and the nature and frequency of potential side-effects of vaccines should be in the public domain;
B. Citizens should have public interest representation on related scientific and medical advisory bodies;
C. Any vaccine used routinely in the programme should be licensed for use in the UK;
D. Any vaccine used in the programme should be subject to regular review;
E. Any adverse reactions should be systematically reported and monitored;
F. Any vaccine offered as part of the programme should be easily accessible and available to all, and free of charge to the patient; as such, equity of access is essential;
G. Vaccines should be administered on a voluntary basis, and only with the informed consent of the patient or, in the case of childhood immunisation, the parent or guardian of that child;
H. There should be general public support for the broad principle of the immunisation programme as a vital part of a public health strategy to prevent, control, eliminate or eradicate diseases at the population level;
I. Parents should be able to access personal advice when making a decision about vaccinating their child, should they wish;
J. The greatest number of children possible should be vaccinated to ensure population immunity and protect the population as a whole, and in particular the very few, very vulnerable children who cannot take a particular vaccine on health or philosophical grounds, and other vulnerable members of the population;
K. Any individual damaged by vaccines in the programme should be compensated on a no-fault basis.

5.28 The Expert Group found this sort of structure both challenging to define, and helpful. Given that the public debate about MMR will likely continue for some time, notwithstanding the substance of the scientific evidence, the Group considers that ongoing dialogue could usefully be structured and facilitated by an agreed, transparent framework along these lines.

5.29 As such, the Expert Group recommends that the JCVI should:

  • develop core principles for immunisation policy in order to provide all interested parties with a clear framework against which any future policy options might be assessed in an open and transparent manner; and

  • continue to publish the conclusions of its regular review of the scientific evidence relating to the safety and efficacy of MMR, and seek to improve on existing arrangements for publicising that material.

5.30 The Expert Group also recommends that Health Ministers (in the UK Government and devolved administrations) should urgently implement existing plans to extend arrangements for appointing members, to the Joint Committee on Vaccination and Immunisation, who are non-medical experts and/or members of the general public.

5.31 The Expert Group also looks to The Scottish Executive to ensure that the level and quality of information available to parents in Scotland whose children are due to be immunised against measles, mumps and rubella, are significantly and urgently improved by:

  • ensuring that all parents receive basic factual information about MMR (for example, contraindications, the risks posed by measles, mumps and rubella, and the risks of adverse reactions) with the invitation to bring their child for immunisation;

  • ensuring that all parents know that they can, and should, discuss any related questions with their GP or health visitor in order to make an informed choice about immunisation;

  • asking HEBS to evaluate and develop"the MMR discussion pack", in order to maintain and enhance the currency and accuracy of the information, training and support provided to GPs and other health professionals, in relation to the medical science underpinning the immunisation programme;

  • requiring NHS Boards to put in place systematic arrangements for providing further advice to parents who, despite discussions with their GP or other health professional, have concerns and questions about MMR or the particular circumstances of their child.

Alternative Immunisation Policies and their Consequences

5.32 There are, in essence, five immunisation policies which might be considered as an alternative to the current policy: no immunisation; compulsory immunisation; deferral of MMR; a choice between either MMR or single vaccines; or single vaccines. The considerations associated with each of these options are set out in the table below and in more detail in the text that follows.

No immunisation

5.33 A small proportion of people have philosophical objections to immunisation. Others, as indicated above, cannot be immunised on medical grounds. None of the submissions presented to the Expert Group question the merit of immunisation against measles, mumps and rubella, more generally. There is therefore a clear and overwhelming consensus that immunisation has been one of the major public health successes of the last century, and that the "no immunisation" policy is not tenable at a population level, because that would:

  • run counter to scientific and medical best practice, and what we know of the views of the population as a whole;

  • lead to a decrease in population immunity and guarantee an increase in the incidence of measles, mumps and rubella.

Compulsory vaccination

5.34 A small proportion of people have philosophical objections to immunisation. Others, as indicated above, cannot be immunised on medical grounds. As such, there would have to be some exceptions to this policy. None of the submissions presented to the Expert Group supported compulsion.

5.35 The Expert Group concluded that such a policy is not consistent with key elements of the framework of principles for immunisation policy. On a practical level, it is not self-evident that it would lead to higher levels of immunisation. More substantively, it runs counter to the Expert Group's core principle that vaccines should be administered on a voluntary basis.

Options, assessed against principles from the immunisation framework

Principle

No immunisation

Compulsory vaccination

Deferral of MMR

MMR or single vaccines

Single Vaccines

Current policy

A - evidence-based validation of safety, quality and efficacy

No

Yes

Yes

Unlicensed vaccines have not been assessed by the MCA against the criteria of safety, quality and efficacy.

Yes

B - public representation scientific advisory bodies

Planned

C - Licensed for use in the UK

Not relevant

Yes

Unlicensed vaccines have not been assessed by the MCA against the criteria of safety, quality and efficacy.
Manufacture and supply issues would need to be addressed for licensed single vaccines

Yes

D - vaccine subject to regular review

Yes
For MMR

E - adverse reactions monitored

Yes

F - Accessible and available, free of charge

Yes

Manufacture and supply issues would need to be addressed for licensed single vaccines

Yes

G - Voluntary

No

Yes

H - General public support

No

Not Known

Yes
But open to interpretation

I - Access to advice

Not relevant

Yes

J - ensure population immunity

No

No
Compulsion does not guarantee high uptake

No

Not Known

Yes
Albeit below optimum 95% uptake

K - Compensation available.

Not relevant

Yes

Yes
If licensed and included in compensation scheme

Yes

Deferral of MMR

5.36 There are, as indicated at paragraph 5.22 et seq above, clinical reasons for postponing MMR. However, the rationale for deferral set out in submissions presented to the Expert Group relate to two separate arguments.

5.37 The first argument is that there is merit in deferring MMR until a child's immune system is "better developed". However, the scientific evidence currently available does not support the conclusion that component vaccines either interfere adversely with each other, or weaken or overwhelm an infant's immune system.While concern has been raised that three live viral vaccines administered together may overwhelm the immune system, the available data that exists does not support this hypothesis. Studies have been conducted where vaccines have been given either separately or at the same time as MMR which directly addresses this issue. If MMR overwhelmed the immune system one would expect reduced responses to vaccines administered at the same time. This is not the case 66.

5.38 The second argument is that deferral allows evidence of standard development (or otherwise) to become more apparent. This is the "coincidence factor" referred to by the HCCC. The major difficulty associated with this strategy, notwithstanding the scientific evidence of no link between MMR and autism, is that, on average, autism is diagnosed at around 4 years of age in the UK. Deferral beyond that age would leave children unprotected for an extended period of time, and put such children, and others, at greater risk of infection.

5.39 The Expert Group recognises that deferring MMR immunisation could be considered both by The Executive (for Scotland as a whole) and by individual parents (for their child). However, the Expert Group concluded that such a policy is not in accord with key elements of the framework of principles for immunisation policy. It is not supported by current scientific evidence, and it leaves children unprotected and at greater risk of infection for longer than is necessary.

MMR or single vaccines

5.40 The Expert Group recognises that some parents wish to be given the choice of a single vaccine for their children, because:

  • of concerns about autism; or

  • of concerns about the concurrent administration of three live vaccines; or

  • both methods are considered to be equally efficacious and effective; or

  • it is a pragmatic way to acknowledge some or all of those concerns and at the same time increase vaccine uptake and population immunity; or

  • choice is a civil right.

5.41 Before addressing these considerations in turn, it is important to recognise a very practical consideration, which is that although single antigen measles and mumps vaccines were previously available in the UK, they are not currently manufactured to UK licence specifications. As such, before this alternative policy could be introduced, vaccine manufacturers would have to begin to produce these vaccines in sufficient quantity and to that standard of quality control. It is not clear how long that would take.

5.42 A case for making single vaccines available by popular choice, as opposed to the clinical judgement of a health professional (as at present, see paragraph 5.24), cannot be sustained on the basis of the available scientific evidence. As indicated in earlier chapters, there is no proven scientific link between the measles, mumps and rubella (MMR) vaccine and autism or Crohn's disease. Another important factor is that even if there were substantive scientific evidence to support the original hypothesised link between autism and measles virus, there is no evidence that the single vaccine option would actually be any safer. Similarly, the scientific evidence supports the conclusion that the component viruses do not interfere with each other 66.

5.43 The efficacy of MMR would be the same as the constituent single vaccines, in relation to providing protection for an individual, subject to issues of manufacture and quality control (which is, as indicated in Chapter 4, a key feature of UK licensing arrangements, but not the importation of unlicensed medicines. A number of different strains are manufactured, and it is important to compare like with like).

5.44 The comparative effectiveness of single vaccines, as part of a childhood immunisation programme is more open to question. There are a number of generally acknowledged drawbacks relating to the issues of both increased susceptibility whilst awaiting immunisation, and the likelihood of vaccinations being missed altogether as six vaccinations would be required, rather than two (and some might not appreciate the importance of giving mumps vaccine to girls, or the rubella vaccine to boys). This would decrease the level of population protection. This is particularly true, if an interval of 1 year was left between vaccinations, as has been recommended by Mr Wakefield and others. The concurrent administration of separate vaccines for measles, mumps and rubella has never been formally tested for either efficacy or safety. Therefore, the best time interval to leave between doses, and the risk of vaccine associated adverse events, are simply not known. In addition, six vaccines would inevitably lead to increased risk of local reactions at the injection site; and increased trauma to the child.

5.45 Advocates of single vaccines maintain that their availability would increase the overall level of population immunity, as they believe that almost all those recently refusing MMR immunisation would consent to separate vaccinations. On the other hand, most health professionals believe that making single vaccines available in this way may well undermine public confidence in immunisation against measles, mumps and rubella, in general. The current level of MMR uptake can be used as an argument either way: it may signal significant public concern about MMR; or nearly 90% of parents may be demonstrating their support for MMR. What is clear is that if single vaccines were available by popular choice, as opposed to the clinical judgement of a health professional (as at present, see paragraph 5.24), protection at individual and population level would depend on the relative proportions of the target population embarking on the MMR and single vaccine programmes.

5.46 Essentially, the extent to which population immunity would be affected by allowing such a choice would depend on several factors:

i) the extent to which this would result in increased vaccine uptake by those who refuse to accept reassurances over the safety of MMR and currently thus leave their children, and others, unprotected;
ii) the extent to which this would change the vaccine uptake decisions taken by those who currently accept MMR;
iii) the extent to which multiple visits would result in increased default; and
iv) the extent to which leaving a space between vaccines rather than using concurrent administration would open up a window within which temporarily unvaccinated children would be at significantly elevated vulnerability to infection.

5.47 The Expert Group noted that the Scottish Centre for Infection and Environmental Health (SCIEH), in collaboration with the University of Strathclyde, is undertaking research with the aim of developing mathematical models which might help demonstrate the range of possible outcomes, for the population as a whole, arising out of decisions made by individual parents. This work is at a very early stage, but in time may help us all to achieve a better understanding of these public health policy options and their effect on the level of immunity in the population. The Expert Group looks to The Scottish Executive to ensure that appropriate resources are provided to allow this work to be carried forward.

5.48 The civil rights argument is not, on its own, compelling, when considered in the light of the Expert Group's framework of principles. It is consistent with some, but not all. The Expert Group recognised that it falls to the Scottish Executive to struggle with the question: given finite resources should the state meet the cost of an individual's desire to access vaccines which could be less effective within the context of an immunisation programme, and which may carry higher risks to the individual and society? Nevertheless, representatives of children with autism and their carers on the Expert Group, including SSA and NAS, were clear that, despite there being no proven scientific evidence of a link between MMR and ASD, on the basis of the currently available evidence, parental concerns are now such as to warrant JCVI revisiting the question whether there should be alternative immunisation arrangements for such families.

5.49 The Expert Group recognised the risks of introducing a dual arrangement for immunisation, for the reasons set out above (paragraphs 5.45-6). The Expert Group also recognises that the Scottish Executive has a duty of care to take account of the body of scientific and medical evidence in order to provide treatment and care which represents best clinical practice. As such, the Expert Group concluded that this alternative immunisation policy is not consistent with key elements of its framework of principles.

Single vaccines instead of MMR

5.50 None of the submissions presented to the Expert Group supported the option of single vaccines replacing MMR in the childhood vaccination programme. However, it is a valid option.

5.51 Most of the considerations outlined above would obviously apply:

  • before this alternative policy could be introduced vaccine manufacturers would have to begin to produce these vaccines in sufficient quantity; it is not clear how long that would take; and

  • a compelling case for single vaccines cannot be sustained on the basis of the available scientific evidence, efficacy or effectiveness.

5.52 As such, the Expert Group concluded that this alternative immunisation policy is not consistent with key elements of its framework of principles.

Chapter 5 - Summary of Key Points

The success of immunisation against measles, mumps and rubella has led to a decline in the incidence of these diseases. As such, the serious associated risks may not be fully appreciated.

There are, of course some children who should not have MMR, at all, or at a particular time. Children receiving immunosuppressive treatment, e.g. for leukaemia or after organ transplantation, are protected by the "population-immunity" that is a product of high immunisation uptake. Children under 1 year old, and unimmunised pregnant women, also rely on population protection for their personal protection.

In considering the range and implications of alternative immunisation policies, the Expert Group developed a framework of principles to guide its thinking. A published JCVI framework of principles may inform and structure further public debate about MMR.

Although single antigen measles and mumps vaccine were previously available in the UK, they are not currently manufactured to UK licence specifications.

The Expert Group considered five alternative immunisation policies:

  • a "no immunisation" policy is not tenable;

  • no one advocated compulsory vaccination or single vaccines replacing MMR;

  • deferring MMR immunisation is not best practice supported by current scientific evidence, and leaves children unprotected and at greater risk of infection for longer;

  • the case for making single vaccines available by popular choice (the MMR or single vaccines option), as opposed to the clinical judgement of a health professional (as at present), cannot be sustained on the available scientific evidence. The efficacy of MMR would be the same as the constituent single vaccines, in relation to providing protection for an individual, subject to issues of manufacture and quality control. The comparative effectiveness of single vaccines is more open to question. It is clear that, if single vaccines were made available in this way protection at individual and population level would depend on:

i) the extent to which this would result in increased vaccine uptake by those who have concerns about MMR and currently leave their children unprotected;
ii) the extent to which this would change the vaccine uptake decisions taken by those who currently accept MMR;
iii) the extent to which multiple visits would result in increased default; and
iv) the extent to which leaving a space between vaccines rather than using concurrent administration would open up a window within which temporarily unvaccinated children would be at significantly elevated vulnerability to infection.

The Expert Group has recommended a range of measures to both continue to review research evidence as it develops, and to give parents better and timely information.