As the controversy over the safety of the MMR vaccine rages on, BBC News Online has brought together protagonists on both sides of the debate to answer your questions.
Dr Nigel Higson, a GP and chairman of the UK's Primary Care Virology Group, believes in the safety of the vaccine and is keen to promote its use.
Jackie Fletcher is the founder of JABS, a support group for families who believe their children were harmed by the vaccine.
Mr Walton, Bracknell:
My son had the MMR vaccine at 15 months however he was three in September and has just contracted measles. What is the success rate of the MMR vaccine and why has he caught measles?
As a support group we cannot give information about the actual diseases themselves - we are a support group for parents who feel their children have been damaged after vaccines. However, the Department of Health claim that the success rate of vaccines is 90 per cent. So there may always be 10 per cent of children although fully vaccinated who may still contract the disease.
Dr. Nigel Higson:
The success rate of a single dose of MMR vaccine is 80 per cent immunity to measles - so out of ten children who have the vaccine, eight will gain immunity after one dose. If we give a second dose, that rate goes up to 96 per cent immunity after two doses, which is why we offer a two dose course of measles, mumps and rubella vaccine as we would do even if we did them separately.
So why has he caught measles? First of all it is a question whether it is true measles and he needs to have his antibodies checked to see if it is, as a lot of things do look like measles. As the immunisation rate has gone down which means more children in the community have the measles virus circulating between them then virus levels go up and children will contract the disease as even if they have the vaccine their immunity may not be perfect. This is another reason why more people should be encouraged to have the MMR vaccine.
Germana Kerr, London, UK:
My four year-old son is due to have the second MMR dose shortly. He did not show any adverse reaction to the first, given at 15 months. I understand that the booster is given to "catch" those children who may have missed on the first dose, or those for whom the first dose did not work. How do I know the first MMR vaccine dose worked for my child? May I not be giving him something that is not needed, putting him at an unnecessary risk?
That is exactly right. Certainly if a child has been given the MMR before, what a parent could request is a simple blood test to look for antibodies for measles, mumps and rubella. The family doctor could arrange this and within a couple weeks would have the results back. From this, parents would have baseline on which to move forward.
So in your opinion, there is no need to have a second jab if the first one has been shown to work?
According to the Department of Health themselves the second one is being given to try and catch the children who were not immune. So by actually checking the immunity first, it would determine which children were already immune and then would not need to be exposed to a second vaccine.
Dr. Nigel Higson:
The only way of determining whether a vaccination has worked is by taking blood off a child and sending it away for immuno-globulin levels. I believe it is more traumatic to a child having blood taken than it is to have a further vaccine. The vaccine is safe - so we don't know without taking blood whether her child has immunity. Two out of every ten children who have the vaccine the first time will not gain the necessary immunity, so it is important that her child does receive the second dose of the MMR vaccine.
Philip Leonard, Doncaster England
Should we not use our common sense and vaccinate, the risk far outweighs the consequences, statistically speaking. How many people have been killed in the past with the MMR diseases? We do not want a return of these killers.
As a group we are not against vaccines but we want safe vaccines. It is this combination MMR - the actual putting together of three live viruses that we are concerned about. We don't want any child damaged by the disease but we don't want them damaged by the vaccine either.
Dr. Nigel Higson:
They were killers and fortunately many of the generation who are now having their children vaccinated have themselves had measles vaccines as child and do not know the terror of measles. Measles is a killer. I know we are talking about mumps, measles and rubella but let me quote for measles itself: in the 1960s the information I have got here, showed 800,000 people in England and Wales caught measles each year in the 1960s before the vaccine were introduced. In 1989 which is a year or two after the introduction of the MMR vaccine, there were fewer than 20,000 people with noted indications of measles - so it had dropped dramatically. So I agree we should use our common sense and get these children vaccinated or else we will see a return of one of the most rapid killers in the world.
Tim Pilcher, London, UK:
I am a father of two (3 years and 7 weeks) - what are the risks, in percentage terms, if: (a) We give our youngest MMR: also what are the potential side effects? ; and (b) We don't: and the possible contraction of mumps, measles or rubella?
That is another reason for looking at the vaccine on an individual basis because each of the three individual diseases have a different ratio of risk benefit to the individual child. For example, with rubella it is only hazardous to someone who is pregnant, so infants are being given the rubella jab for the sake of the community. Now most parents would be happy to do that but at the very least they should be aware that the child is being given this for the community rather than for the individual child's sake.
What about the risk of MMR itself - in percentage terms have you any idea how many people suffer side-effects?
Well certainly the numbers who have contacted the JABS group are very alarming. We have 1,800 children registered with us believed to have been affected by this combination measles, mumps, rubella vaccine. These children were given the vaccine at all ages; some received it for the first time when they were thirty months or eight or even fifteen years old. According to the parents, these children have reacted usually within the incubation period of the vaccine they have been given with symptoms known to the manufacturer - it is the combination that we have the concerns with.
With the single measles jab, that has got a much safer track record in Britain; it was used for twenty-one years and we have got twenty seven children on our books believed to have been affected. Comparing this with the MMR used for twelve years and having 1,800 believed to have been affected - something is wrong and needs to be investigated by the Department of Health.
Dr. Nigel Higson:
Certainly at the age of seven weeks we don't give MMR anyway so I presume he is talking about when the child is over one year-old. The risks for an individual depends on the uptake rate in the local community. The significant side-effects are something like 1 in every 100,000 injections - so it is a very low risk of significant side-effects. If he lives in an area of high uptake of vaccination then there is less concern however if everybody takes the same principle, the rates of vaccination will then go down and the risk is greater. So it is playing the odds and not knowing what the outcome of the race is going to be until it has happens.
So we can't give an individual risk assessment. I would encourage him to have his youngest child vaccinated against MMR when he is invited to have that done between one year and fifteen months.
Richard Taylor, Guildford, UK:
Has the incidence of autism increased, decreased or stayed the same since the MMR was introduced in the UK?
Certainly the National Autistic Society, the Allergy Induced Autism Society and many other health professionals have been in touch with us to say that they are concerned that there is an alarming increase in the number of children falling into the autistic spectrum. The Department of Health claim that it is just better diagnosis, but this is something that has developed in the last twelve years. These same paediatricians, with perhaps twenty or thirty years experience of examining children, haven't suddenly learnt better ways to do it - these are experienced consultants who are diagnosing these children.
Dr. Nigel Higson:
There is no relationship of MMR to autism. I say that bluntly and clearly. Studies in Sweden and Finland have shown there is certainly no links MMR and autism. These studies show those children who have been given MMR had less autism than those children who hadn't had it done. It is like any research there are many different stories. There is no link between MMR and autism - full stop. However, autism is a complex range of diseases and what has happened with autism in the last 30 - 40 years is that there have been a lot more syndromes recognised which are all classed together as autism. So the number of children diagnosed with autism has increased because the diagnosis has been changed.
Chris Greenfield, London, England:
Why are other countries not combining the MMR as we do in the UK? Is the vaccine safer when administered individually?
In other European countries and in America the MMR vaccine is the routine vaccine offered to children. But, if parents don't want it, for any reason, they can choose the single vaccine if they want. Most health practitioners are taking the line that it doesn't matter as long as the child is vaccinated. As to whether the individual vaccine is safer - going from the track record in Britain, as I mentioned before, the single measles jab was brought in, in 1967 and used for twenty-one years in the UK - it was the main vaccine given to babies. We have got twenty-seven children on our books from that time-frame, so it appears more like a one-in-a-million chance if a child does have a problem.
There is still a risk from the single vaccine and parents should ask their health practitioner for full details of the manufacturer's information - not the glossy printed pamphlets but the contents of the vaccines and the contra-indications. In fact in hindsight some of the families of the twenty-seven children affected have discovered there were medical reasons why the child should not even have been offered the single vaccine. Parents should have the choice.
Dr. Nigel Higson:
Firstly, the majority of developed countries in the world who can afford vaccination now use MMR primarily for vaccination against measles, mumps and rubella. It has been used for approximately twenty years in the USA, fifteen years or so in the UK and in Canada and the last ten to fifteen years in most of the European countries, New Zealand, - I don't know for sure but also most of the Far East as well. There are a considerable number of children vaccinated throughout the world every year with MMR vaccines. In France, where a lot of children are now being given the single dose measles vaccine, they give single dose measles at eight months and then they give two further doses of MMR after a year and at three years. So in fact some of the countries that parents are saying only use single dose vaccine - yes, they might use a single dose vaccine but they do use MMR as well. MMR is trusted and is used widely throughout the western world.
Secondly, is the vaccine safe when administered individually? The simple answer to that is - no it is not. If I give a child a vaccination I am assaulting that child with a needle; I am putting the needle through the skin into the subcutaneous tissue - every time I put an injection into it, there is a potential for tissue damage. So the more combination vaccines I can use, the less damage and less distress there is to that child. So they are not safer when administered individually and as far as these links with any other disease, there is no link at all.
What about the level of immunisation that the individual vaccine offers in comparison to the triple vaccine rather than the fact that it means the child has to have more injections?
Dr. Nigel Higson:
The combined vaccine MMR offers greater immunity because they potentiate each other by giving measles, mumps, and rubella at the same time, the body undergoes an immunological response which gives more immunity than if given individually. If it were given individually we would perhaps get 70 per cent immunity from the measles vaccine whereas when given the MMR we get 80 per cent.
Are there statistics available to show that where the individual vaccines are used more disease is prevalent?
Dr. Nigel Higson:
Not in the UK. Certainly not in the USA or most of Europe. If you are going to get statistics like that, based on current available vaccines, you are probably looking at the Third World, which makes research very difficult. So I don't think there are statistics easily available on that.
I think again it was Dr David Salisbury who made the point, that the individual vaccines for measles, mumps and rubella have to be given fairly widely spaced apart and during that time a child would not be protected whereas when they have the triple vaccine they are protected immediately for all three conditions.
On that point again it is down to looking at the individual diseases. Measles is something that all children could do with being protected against and parents should have the choice of a single vaccine. The families coming to us who want to vaccinate their children are calling for the measles vaccine - that is one that perhaps should be considered first as it the most serious of the three diseases. Rubella is of no consequence to anyone not at risk of being pregnant, so if it was last on the list, the child itself is not being exposed to any greater danger. By all means educate females of child-bearing age to make sure that they are immune to rubella before they plan a pregnancy but it could be last on the list so far as the child is concerned. Mumps - it can also be a single vaccine - it usually has been seen as a more of a problem for teenage boys so if it was second on the list, I cannot see how you are exposing an individual child to any greater degree of danger.
Kyle MacRae, Glasgow, UK:
Is the current MMR programme merely a mass nation-wide experiment that will, by accident or design, determine the safety of otherwise of this vaccine?
We know from the research that we have been doing that the pre-license trials conducted by the public health laboratories in the UK, only lasted twenty-one days. This is wholly inadequate for three live viruses together. World-wide - we have only been able to find a four week period which again seems to be inadequate.
Dr. Nigel Higson:
This is obviously a conspiracy theory. No it is not a mass nation-wide experiment. It is a mass, nation-wide attempt to decrease and eradicate a major killer - being measles as well as decreasing the incidence of mumps and rubella syndrome. So it is not an experiment - the vaccine has been proven in twenty years or more of use in the USA, fifteen years in the UK and in many other countries, to be a safe vaccine which is effective in controlling these diseases.
Steve Bow, Bradford, UK:
The official line seems to be that there is no proven link between MMR and autism or Crohn's Disease. Whether there is a proven link or not is not the point as far as I am concerned, as the parent of a child who now of the age to receive MMR, I want the choice of having the vaccines administered separately. I am currently being denied this choice - why is that?
Whether the Department of Health like it or not, there is a question mark over the safety of the triple vaccine. Six hundred Legal Aid certificates have been awarded to parents to pursue a case through the courts to determine the safety or not of the MMR vaccine. So while the jury is out, parents should have the right to choose single vaccines.
Dr. Nigel Higson:
The UK is not a society whereby things are inflicted upon us or our children so that the state benefits. There is a community benefit to everybody having the vaccination because it stops the spread of disease. There is an argument to say that if enough people don't have their children vaccinated, they are therefore putting their neighbours' children at risk and their neighbours might sue them for spreading disease. Now that is a very complex legal argument which has never been tested.
So should we have single vaccines? I personally believe in the MMR, as do the majority of doctors in the UK and certainly so does the Department of Health. It is a safe vaccine. However, I have patients who prefer to have the single vaccine and they have gone elsewhere to have this done. I believe that the UK should licence single vaccines for specialist-centre use only. It should not be an easy option. It should be an option that is only available at certain areas in the UK which have to be referred on by the GP or paediatrician at the local hospital for consideration of vaccination. The reason I say this is because our aim is to decrease measles and I would rather give a child a single vaccine of measles if they really refused MMR than not given anything at all.
Mike Dunn, Sussex, UK:
Is it ethical for doctors to be paid a bonus for each child they vaccinate?
Certainly from JABS' point of view, we do wonder whether this questions the integrity of the vaccine decision. I would feel happier if they gave a bonus for every adverse reaction that was reported by the parents.
Dr. Nigel Higson:
We are not paid for individual child vaccination. We used to be paid a bonus for each child, we are not paid that anymore. We are paid to achieve a community target. In other words, within my own practice, if we achieve a target of 70 per cent of our children receiving vaccines, we receive a payment, if we achieve a target of 90 per cent, we get a higher payment. So there is a bonus for working that bit harder to try to get the children vaccinated. The Department of Health felt that by giving an incentive system to GPs they would achieve a better health status for the UK than they would by the previous method.
Suzanna Cardash, London, UK
Is there any concern over the single dose measles or mumps vaccines? Are they, too, linked with Crohn's, autism or other disabilities?
All vaccines carry a risk and the risk benefit will be different for each particular vaccine. What we suggest to parents is that they get as much accurate information on the childhood diseases, which they can get at any library and asking for copies of medical textbooks from the early sixties prior to the vaccines coming out in 1967 onwards. That would give them accurate information on the diseases. They could also request a copy of the drug manufacturer's information on any vaccine - even the single - from their GP or any chemist. That information will tell you the contents of the vaccine, when not to give it and the side-effects that drug companies have encountered when introducing the product.
Dr. Nigel Higson:
The MMR is not linked to Crohn's, autism or any other disabilities. There is no research that I know of that has compared the single antigen vaccine of measles, or mumps or rubella. This is something which has been a point of concern in Wakefield's original study where he raised these queries - so no, there is no research showing there is any link of the individual vaccine to any other disease, specifically not Crohn's, autism or other disabilities. Similarly, there is no concern about MMR being linked to any of these diseases or conditions.