Why is MMR in the news again?
New research may have found a definite link between autism and the MMR (measles, mumps and rubella) vaccine. Previous studies have largely relied on statistical methods to spot a very small possible effect in a very noisy background. The new work, performed by Dr Vijendra Singh at Utah University, tried to find a direct biological link between autism and the vaccination. He appears to have found it but the study needs to be repeated by other researchers before it is likely to be accepted by doctors.
What did Dr Singh's team discover?
He found a "significant increase" in antibodies that attack the covering of nerve fibres in children with autism that had been vaccinated with the MMR vaccine. It appears that a very tiny minority of children produce antibodies that attack the measles virus - but also mistakenly attack the covering of nerve fibres. This, he believes, could lead to autism.
Dr Singh's team analysed blood samples from 125 autistic children and 92 children who did not have the disorder. Part of the measles component of the vaccine caused the unusual anti-measles response in 75 of the autistic children but not in the normal children. More than 90% of the autistic samples which showed an immune response to the measles component of MMR were also positive for the antibodies thought to be involved in autism.
Is the MMR vaccine dangerous?
The balance of medical evidence suggests it is not dangerous. Dr Singh's work, if confirmed by other researchers, suggests that for a very small minority of children the vaccine may be linked to autism. However other studies suggest MMR is safe. Finnish researchers followed 2m children for 14 years after they received the MMR vaccine and found no evidence that the vaccination resulted in later health problems. The government says the vaccine is perfectly safe. But many parents are still concerned.
Who gets the MMR jab and when?
The vaccine is currently given to children twice, once at about a year old and the second time at about four years old. The second injection is intended to catch anyone who missed out on the first one and to provide protection to any children who may not have been fully immunised by the first jab. Before MMR, children received separate vaccinations for each disease.
What does the health profession say?
Nearly half of family doctors, health visitors and practice nurses have reservations about giving children their second dose of the MMR vaccine, according to recently published research. However, only 3% actually disagreed with the policy of giving two injections, and many of the objections had to do with subjecting children to two needles rather than with the health risks.
There's not much measles, mumps and rubella around today in this country, so why do we still need the vaccine?
The success of vaccinations in defeating diseases depends upon the vast majority - about 95% - of the population receiving the vaccine. If a significant number of parents stopped giving MMR to their children, then health experts say the diseases could reach epidemic proportions. The immunisation level in the UK has dropped to 88% overall and down to 75% in some areas. Government health experts say an epidemic could be just around the corner. The last UK outbreak in 1980 killed 17 people.
If the disease is dangerous and the vaccination is dangerous, what is the alternative?
Some suggest that it is safer to give children the separate vaccines for measles, mumps and rubella. It is only the combined vaccine that has been linked to autism and bowel disease.
So why not administer the vaccines separately?
The problem is that in the time between the vaccinations, children can catch one of the diseases. The head of vaccination at the Department of Health, Dr David Salisbury, sites the example of Japan, where the vaccinations are administered separately and 79 people died from measles between 1992 and 1997.
What should parents do?
Many parents are choosing to give their children only the first vaccination at between 12 and 15 months old. Of course some are choosing not to vaccinate at all, even though that carries the risk of a measles epidemic.
