What is the MMR jab? Is it safe?

There is no evidence to suggest that MMR – the triple vaccine for measles mumps and rubella – is unsafe. More than 500 million doses have been administered in 90 countries since the 1970s, and international research has concluded that no deaths have been linked to it, or any permanent damage caused. It was first used in Britain in 1988 to replace single vaccines for each of the illnesses, and is recommended for all children aged 12 and 13 months old in two doses.

So what's all the fuss about?

In 1998 a study of 12 children by Dr Andrew Wakefield and colleagues, published in the medical journal The Lancet suggested the jab might trigger bowel conditions in children that led to autism. As a result many parents demanded single vaccines instead. The Department of Health refused and public confidence plummeted. Some parents had their children vaccinated privately, using single vaccines for each disease – although there is no evidence to suggest this is safer - while others decided not to have their children vaccinated at all.

Is there anything to these fears?

Few experts still take Dr Wakefield's findings seriously as they have been disproved by numerous studies.

Rates of autism and related disorders have been increasing in recent years, but no research has been published to substantiate that this has anything to do with MMR or associated bowel disease. Studies involving millions of vaccinated and unvaccinated children have shown no difference in rates of autism between the two groups. All have concluded that the three-in-one MMR jab is safe. In 2004, The Lancet and many of Dr Wakefield's co-authors retracted contentious parts of the paper, saying they had been wrong to publish the research.

What is the result if children aren't vaccinated?

Low uptake of the MMR vaccine has been blamed for a resurgence of measles in Britain, a contagious disease which can be fatal. Last year there were 1,348 measles cases in England and Wales. In 1998 there were just 56 cases.

Campaigns to immunise schoolchildren with MMR are being carried out around the country to prevent an epidemic, which could affect an estimated 100,000 children.

So what's happening to Andrew Wakefield?

Since July 2007 he has been appearing before a fitness-to-practise panel of the General Medical Council, along with two co-authors of the research, accused of serious professional misconduct.

The charges against Dr Wakefield include accusations that 11 children were subjected to invasive tests such as colonoscopies and lumbar punctures that were contrary to their best clinical interests.

Dr Wakefield is accused of not having the “requisite paediatric qualifications” or of not seeking the right approval for the tests. He is also accused of acting “dishonestly and irresponsibly” in failing to disclose how he recruited patients to the study. The hearing was told that Dr Wakefield paid children £5 for their blood samples at his son's birthday party.

Another of the key allegations is that Dr Wakefield was being paid at the time for advising solicitors on legal action by parents who believed their children had been harmed by MMR.

He is also accused of abusing his position of trust and bringing the medical profession into disrepute.

Dr Wakefield denies any wrongdoing.

The long-running hearing is not due to conclude until this summer.

Sources: Times database, Health Protection Agency, GMC, Department of Health

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