A wise doctor once observed to a new batch of medical students that in 20 years’ time, half of what they were about to be taught would be proved wrong. The problem, he added, was that nobody knew which half. The widespread mistrust of vaccination programmes might be lessened were the Government and medical establishment to stop trying to insist that they are 100 per cent right. Medicine is an imperfect science.

In the context of imperfect science, there is no evidence that the measles, mumps and rubella (MMR) triple vaccine does significant damage to the children who receive it. There is strong evidence that all childhood vaccinations protect society, and individuals, against a range of diseases that can lead to blindness, paralysis and death. After six years of scaremongering about the safety of the MMR vaccine, the claims of the scientist Andrew Wakefield, who sounded the alarm, have been disowned not only by The Lancet, where they were published, but also by ten of the co-authors of the paper.

That Dr Wakefield was afforded such credibility was in part a consequence of a culture and a media mistrustful of authority and more inclined to put their faith in rumour and conspiracy theory than in science and common sense. That the debate reached the pitch it did was also, however, because some of those who disagreed with Dr Wakefield resorted to personal abuse and would not admit to any doubt on questions about the efficacy or safety of childhood vaccination. If Dr Wakefield and his fellow sceptics have been guilty of hyperbole and ill-founded aspersion, then so too are some of those who derided him. A debate that cried out to be conducted in measured tones and in the light of cold scientific fact was taken hostage by the extreme opinion and emotion: parents vacillated, and vaccination levels plummeted.

This apparent fear of debate raised, and continues to raise, suspicion. At its heart is a belief that the man in Whitehall and the white coat knows best, and that parents are irrational, irresponsible creatures incapable of making informed judgments about what is best for their children. Admit that a vaccine may be less than 100 per cent effective, and a parent will not bother to vaccinate her child? The level of ignorance and inertia that such an assumption makes about parents is patronising and arrogant, even if it is well intended and socially conscious.

There are occasionally valid concerns about the safety and efficacy of vaccination, and parents are right to raise them. It remains a valid question, for instance, why the vaccine strain of measles virus is unusually frequently present in the gut of autistic children. Vaccination is booming business. Today’s grandparents received only the smallpox vaccine in childhood; their grandchildren are given no fewer than six vaccine doses at just eight weeks old.

Government is slow to catch up with trends: it still vaccinates against polio as a matter of course, although the disease has been eradicated, yet tuberculosis vaccination is only offered sporadically to infants, even though 375 people in England and Wales died of the disease in 2001. Medical staff may, for example, be unaware of the “real” age of babies born prematurely before they vaccinate them, and are often unable to divine the precise provenance of a vaccine.

None of this inspires confidence among parents. What they need is as much information as possible to enable them to balance the relative risks. Most will then decide upon vaccination. But when the sanity of science is eroded by the emotion of medical point-scoring, the temptation is for parents to shrug in disbelief.