What is it for?
Gives immunity to measles, mumps and rubella (German measles)

How dangerous are these?
Measles kills one in 10,000 cases and has side effects in one in 15 cases, ranging from temporary to permanent hearing loss to severe brain damage. Mumps can cause life-threatening viral meningitis and male infertility. Rubella can cause stillbirths and birth defects if caught when pregnant

When is it given?
At 13-15 months, the point at which maternal immunity wears off. About 10% of children do not develop antibodies, so a pre-school booster is given

Is it mandatory?
Not in Britain. Rates are below 55% in some areas because of the scare

How many children have had it?
More than 500m worldwide

What was there before MMR?
Measles vaccine used to be given to infants from age one. Rubella vaccine was given to girls aged 10 to 13

What are the recognised side effects of MMR?
Slight fever or rash lasting about two or three days. Swelling of the glands in the cheeks, as seen in mumps, happens in about one in 100 cases. In one in 1,000 cases convulsions occur

THE WAKEFIELD CONTROVERSY

What is it about?
In 1998 Wakefield’s team published a study in The Lancet. It claimed two findings: that MMR was associated by parents with the onset of autism in eight of the 12 children studied (66%); and that the children had bowel disease

Do these findings stand in the wake of The Sunday Times investigation?
The editor of The Lancet said yesterday the MMR/autism link was “entirely flawed” and should never have been published

Is the bowel problem important?
Not as regards MMR

What else does the Wakefield camp say?
They say further studies have found evidence of the measles virus in the diseased guts of 91 children

Is this important?
The vast majority of scientists say it is not and that measles virus is ubiquitous

Might single jabs be better?
Wakefield suggested this but experts say his thinking is muddled

A single jab of measles also contains the measles virus, so what is the difference?
Wakefield has suggested that the triple jab might “overload” the immune system, making it easier for the measles virus to attack the gut

Is there serious evidence for this?
No

Even if it were true, would it prove a link with autism?
No

Are there any other studies of MMR and autism?
Several large epidemiological studies have found no link. Even Wakefield concedes that if damage is being done, it affects a tiny number of children

Is there any other relevant science?
The National Autism Society says regressive autism (the type targeted by Wakefield) has remained constant since the introduction of MMR

Why, then, do parents make the link?
Regressive autism occures naturally in a tiny number of children at about the time the MMR vaccine is given

Is ordinary autism increasing?
The numbers are up but most experts say this is because the definition has changed and diagnosis has improved markedly.

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