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General Information

Why is MMR preferable to single vaccines?


In the last 3 years increased incidence of measles has raised concerns about potential measles epidemic that are likely to occur due to continuing low uptake of the MMR vaccine (against measles, mumps and rubella) and accumulating numbers of unprotected children in the UK. Uptake of the vaccine amongst two-year-olds in the UK has declined from around 92% in early 1995 to around 80% in the 2003/4. The World Health Organization recommends immunity levels of around 95% to prevent outbreaks of disease.

MMR uptake fell in 1997 in the UK following publicity about speculation that the MMR vaccine might be linked with autism and Crohn's disease. These concerns have been investigated by the PHLS (now HPA) and others, and have been firmly refuted - MMR remains the most effective and safest way of protecting children against these dangerous diseases, and parents are urged to have their children vaccinated with MMR.

One of the myths circulating in the press is that the vaccine has been inadequately tested for safety. This information is wrong; there is extensive high quality information to back up the safety of MMR.

Further information is available on the NHS Choices website: MMR immunisation pages.

Why are single vaccines against measles, mumps and rubella are not routinely offered?

There are no health benefits from using single vaccines in preference to MMR and a number of reasons why they are a bad idea:

  • Single vaccines are less safe than MMR because they leave children vulnerable to disease for longer.

With single vaccines, children would need six separate injections. This would involve three "primary" doses, one of measles, one mumps and one rubella, followed by three separate pre-school boosters. The gaps needed between the vaccines are unknown because the theory is not based upon any evidence at all. This would leave the child vulnerable to dangerous diseases for longer: After the first injection, the child still has no immunity to the other two diseases against which they are unvaccinated. This is less safe than with MMR, where most children are given good protection by a single dose given at about 12-15 months and protection is virtually complete by dose two, given as a pre-school booster is given to catch any children in whom the first dose did not stimulate a full immune response.

Delaying immunisations by splitting them in this way therefore has a similar effect to reducing the proportion of children immunised. More children are unprotected, increasing the risk to themselves and to other children.

  • All the evidence suggests that uptake is in fact poorer with single vaccines than with the MMR, and so with single vaccines fewer children would be protected. With six injections it is very likely that many children would not complete the course and therefore, to suggest that giving six injections rather than two will improve uptake is incorrect.

Giving MMR separately as six injections instead of two would increase the discomfort for children three fold, since each injection can be uncomfortable and the act of immunisation is sometimes distressing for children.

Some people argue that making single vaccines available would improve uptake because parents who refuse the MMR would take the single vaccines. In fact, the evidence from the UK and elsewhere is that the opposite is true. One of the most striking features of the replacement of single measles vaccine with MMR in 1988 in this country is the significant improvement in vaccination uptake which followed.

  • Single vaccines imported into this country have not been independently tested for potency and toxicity - we have evidence that some of the single vaccines are less effective or less safe than MMR.

Unlike MMR, where the evidence shows no link, no study has been conducted to look at single vaccines and either autism or bowel disease. In fact, there is no reason to think that single vaccines would be any less likely to cause autism or bowel disease than MMR.

Parents are asking for these vaccines because they are scared by all the unfounded stories they have heard and read about MMR, not because there is any evidence that single vaccines are any safer.

If children do not have protection against all three of these diseases, we run the risk of the resurgence of the infections. This means not just measles outbreaks, but, for example, the return of babies born with terrible defects as a result of congenital rubella syndrome, or of children becoming deaf following mumps.

No country in the world recommends vaccination with the three separate vaccines - the UK is unique in this scare story. Some single vaccines are available in other European countries, where they may be used rarely in special circumstances (for example in France measles vaccine is used for children aged 9 to 12 months attending nursery schools. These children usually go on to have MMR six months later).

Why should parents trust the Government?

Many people feel they cannot trust Government past issues with food safety such as BSE. However, vaccination is completely different from other areas such as food safety. The vaccines are recommended for our children on the advice of independent expert groups, not the government. MMR is the vaccine of choice in more than 100 countries worldwide. An extensive national and international network of specialists provide advice based on decades of experience of running a highly successful national vaccination programme which has successfully eradicated smallpox and controlled terrible diseases including polio, diphtheria, whooping cough, and meningitis. These professionals have a responsibility and mission to protect children's health. They include NHS and HPA (formerly the Public Health Laboratory Service) public health doctors and nurses, paediatricians, immunologists and others including all the UK professional bodies such as the Royal College of General Practitioners and the World Health Organization. Why would they be promoting a vaccine if it were not as safe as possible?

What we don't want to see in the UK is a similar situation to the whooping cough vaccine scare story of the 1970s when single whooping cough vaccines were offered to parents, and vaccination uptake fell to 30%. Large epidemics of whooping cough resulted, with over 100,000 cases notified, and it took 15 years for coverage to improve enough to control whooping cough again. No one in public health wants to repeat this experience with measles.

Changes in the NHS have occurred following the Bristol enquiry, with new bodies such as the National Institute for Clinical Excellence (NICE) and the Centre for Health Improvement (CHI) all directed at ensuring that the NHS provides evidence-based best practice. In this context, it is the responsibility of doctors and nurses throughout the NHS to advise parents on what is best for their child. Having reviewed the evidence, all professional bodies support MMR as the safest way to protect children and recommending single vaccines runs counter to this available evidence.

Why can't parents choose?

Parents are free to choose whether to protect their children as no vaccination is compulsory in the UK, and the majority follow the good advice of their health visitor, practice nurse or GP and protect their children with MMR. The NHS has a responsibility to offer the best available protection, which is MMR. Some parents, such as all of those with children too young to be vaccinated or with health problems such as leukaemia (who cannot be given live vaccines), have no choice; their child can only be protected if vaccination uptake is high in all other children.

Taking all these points together, there is no reason to make single vaccines available and every reason not to.

Exhaustive research to test the possibility that MMR may be linked to side effects like autism has found good evidence that it is not linked with these conditions.

However, there is much evidence

  • of the benefit of MMR in preventing disease;
  • of the drawbacks of single vaccines;
  • and of the very serious consequences of the diseases themselves.

Introducing single vaccines would fly entirely in the face of all the evidence, and would therefore probably serve only to further undermine public confidence in vaccines.

It is important that we remind people about the dangers of the diseases we are trying to prevent, about the strong evidence for the safety and effectiveness of MMR vaccine, and about the importance of having their child vaccinated with MMR.

To summarise:

  • The MMR vaccine has been thoroughly investigated and is very safe

  • Single vaccines should not be recommended in the NHS because

  • Single vaccines leave children vulnerable to the diseases for a longer period of time

    • Using single vaccines in this way is experimental

    • There is no evidence on what schedules (spacing) should be used and inadequate evidence of safety and effectiveness of using single vaccines in this way
    • Past experience shows that uptake of single vaccines will be lower. When measles and rubella vaccines were used separately, children continued to get measles and babies were born with congenital rubella. When MMR was introduced, measles and congenital rubella were virtually eliminated
    • It is unfair and unkind to give a child six injections unnecessarily when they can be better protected by just two.
    • Offering single vaccines to parents when all the evidence indicates that this is likely to put children in the UK at risk runs counter to all recent initiatives to make NHS practice evidence-based, following for example the Bristol enquiry and the establishment of the National Institute for Clinical Excellence (NICE)
    • Past experience of a whooping cough vaccine scare in the 1970s shows that if we offer single vaccines, the vaccination programme may collapse, with devastating consequences for children
  • If parents do try to get single vaccines from clinics, we urge those parents to ask:
    • exactly which vaccine they are being offered;
    • when and where that vaccine was tested;
    • what the results of those tests were in terms of the safety, potency and purity of the vaccine;
    • what post-vaccination follow-up of their child is offered by the clinic.