THE controversy over the MMR vaccine and its alleged link to autism and Crohn's disease in children continues to rage on, leaving many parents scared and confused.

Dr Robert Aston, the communicable disease consultant for Wigan and Bolton Health Authority, helped launch the combined jab in the 1990s and is a leading expert on the issue.

Here, he argues strongly in favour of parents giving their children the vaccine, citing that there is no evidence to suggest the MMR jab is dangerous.

The MMR vaccine has been used for over 20 years in more than 90 countries with over 500 million doses given. The scientific evidence for its safety and effectiveness is enormous and at least as good as for any other vaccine.

Every reputable medical, nursing and scientific organisation in the world that has looked at the allegations of a supposed link with autism has declared that there is no such link.

The present controversy is little to do with these facts. It is to do with scares and irrational fears and systematic undermining of parents' confidence.

The parents who have become convinced that their children have autism as a result of MMR are genuine, loving people, and I respect their conviction.

Autism, however, typically shows its first signs during the second year of life, and MMR is given to over 90 per cent of children at the beginning of that year.

We do not know the cause (or more probably causes) of autism, but there is a deep human psychological need to find a reason for tragedies in our lives.

When anti-vaccine campaigners consistently and very publicly state the untruth that MMR causes autism, it is hardly surprising that parents of autistic children see this as a reason and explanation for their suffering.

But personal conviction, no matter how sincere and total, is not a good guide to fact.

Let me tell a true story to show this. A young man called Tom died six years ago at the age of 19 from a progressively paralysing illness which started a few days after he had his vaccines at the age of three.

On investigation, he was found to have muscular dystrophy, a condition which is present from the moment of conception, but which often shows its first signs around the age of three.

His condition had absolutely nothing to do with his vaccinations. But if Tom had had any condition for which we do not yet know the cause, such as autism or Crohn's disease, who could possibly have blamed his parents if they had become totally and sincerely convinced that it was caused by the vaccines?

It is perfectly possible to be sincerely convinced of something, but be wrong.

In case readers should think me heartless or unaware of the suffering of the parents of children with conditions like autism, it is important to add that Tom was my own son.

Truth cannot be determined by personal conviction, no matter how strong and sincere.

Indeed, if your conviction is in fact wrong as demonstrated by world evidence, but you continue to state it publicly as fact, you might not only be deceiving yourself, but also mislead others.

You may be causing unnecessary alarm and pain to other parents and undermining their confidence, so that they do not protect their own children from dangerous diseases.

If you want to find out if MMR causes autism, one way is to look at large numbers of children over many years and find out if autism is more common in children who have had MMR. It is not.

Another is to look at the levels of autism. This has been rising over the years, but the rise started well before MMR was introduced.

When MMR levels have remained the same, autism has continued to rise. When there has been rapid increases in MMR vaccinations there has been no corresponding rise in autism.

So, why is there so much controversy and public concern?

There has been sustained activity by anti-vaccination groups (some of them claiming not to be against vaccination but only ever undermining public confidence in this safest and best way to protect our children), lawyers who support their claims, irresponsible media coverage promoting theories for which there is no evidence and indeed much evidence to the contrary.

This is hardly surprising in a "compensation culture" supported by irresponsible media preference for sensational controversy rather than the sober reality of safety.

Sensation sells, safety does not.

A very similar scare occurred in the 1970s when one medical team, with no evidence for it, promoted the idea that the whooping cough (pertussis) vaccine caused brain damage.

Because true scientific study takes time, it was three years before it was clear that there was no such connection.

The Department of Health gave in to the public alarm and pressure groups and agreed to separate the diphtheria, tetanus, and pertussis vaccines. The result was a catastrophic fall in take-up. By the time public confidence was restored, the damage had been done.

An estimated 300,000 children suffered from this dreadful disease because parents had been scared into not having them immunised, and at least 70 of them died. Sadly, we do not seem to learn from history and are falling into the same folly all over again with MMR.

Giving separate vaccines would not only give no benefit over MMR, but would clearly increase the risk of serious disease for our children. The overwhelming scientific evidence for the overall safety of MMR vaccine and of no link with autism has been presented publicly over and over again, made available through leaflets, public health campaigns, and through comprehensive fact sheets distributed through doctors' surgeries and health clinics.

I close with an appeal to the parents of the over 96 per cent of Bolton's children who have safely had the MMR vaccine by the age of five years, the "silent majority" - please consider taking a moment to help to stop this current national folly by making your support known. Why not start by writing to the BEN, your MP, or your local councillor to support MMR as the best and safest way of protecting our children?

For more information, fact sheets are available from all GP surgeries, health clinics, or NHS Direct on 0845 46 47.

If you want reliable information on the Internet, please do not go to the campaigning sites, instead

Click HERE

or Click HERE