Vaccination has revolutionised public health, so why is it now being viewed with such suspicion? Anna Fazackerley finds out

Talk of a global outbreak of a new strain of killer influenza has been circulating for some time. Chilling warnings of a repeat performance of the 1918 pandemic, when 70 million people died across the world, make it easy for the media to whip up panic every time the winter flu season comes around.

Last week newspapers were demanding to know why the government wasn't embarking on a major vaccination programme for British children, as fears of an "unexpected" Fujian strain of flu began to spread. But while academics specialising in health are in little doubt that the risk is real, some are less certain that the public would accept a government push for mass immunisation.

There is a feeling among academics that suggestions of a link between the measles, mumps and rubella vaccine and autism, made by a small group of scientists in the late 1990s, may have done lasting damage to public trust of vaccines. This piece of research was widely panned by scientists and has never been repeated successfully. But the media coverage of the potential link (which far outweighed coverage of scepticism about the research) has had a negative impact on take-up of the vaccine. According to government statistics, 82 per cent of two-year-olds were given the vaccine last year - the worst uptake since 1989. In some areas the take-up had dropped below 60 per cent, increasing the risk of a serious measles outbreak.

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Dick Heller, professor of public health at the University of Manchester's faculty of medicine, says: "It's pretty well known that measles isn't a benign illness. A proportion of kids actually die and others get encephalitis."

There are several theories about why people are turning away from the vaccine. Heller argues that it says much about public mistrust of politicians. "People have been falsely reassured about things in the past. We have so many examples of spin, people just don't believe it."

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He thinks parents are listening to reassurances about the safety of the vaccine and remembering images such as John Gummer feeding his daughter Cordelia a hamburger in the midst of the BSE scare.

Andy Alaszewski, professor of health studies at the University of Kent at Canterbury, says a key problem is that people aren't very good at making risk-based decisions. He explains that the MMR scare is a prime example of risk amplification.

In a recent study, Alaszewski asked subjects to assess a variety of different risks. He found that people tended to overestimate low-probability events with a high consequence, such as dying in a rail crash. This pattern of distortion is reinforced by the fact that these are exactly the sorts of events that the media pay most attention to.

"The MMR autism case was a low probability with a high consequence for the individual. Parents had to weigh up the low probability of having their child damaged by autism versus the high-probability, low-consequence of measles," he says.

Alaszewski says that such views are often not a result of ignorance. "The problem is if you provide more scientific evidence, it doesn't necessarily change people's perceptions."

Eileen Rubery, a lecturer in public policy at the Judge Institute of Management at the University of Cambridge, says the government has not made any real attempt to understand the public's point of view. She argues that the Department of Health has acted complacently, telling parents that the government knows what is best for their children.

Last week The Sun complained that worried parents were being given contradictory information about the MMR vaccine and didn't know who to believe. Indeed, in a simple trawl of the web it is more difficult to find a site explaining the merits of immunisation than to find one reinforcing fears about its dangers.

Rubery, who used to run the DoH immunisation programme, says the department should work harder to communicate the risks of opting out of vaccination.

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"They should show the film footage of the 1918 flu epidemic, with people dropping dead in the street," she says. "People fear vaccination as they see alleged side-effects. You have to do a visual thing on the other side."

Rubery argues that the key obstacle to vaccination is that people don't realise how successful it has been. "GPs in their 50s or 60s will say vaccination has transformed their jobs. It has wiped out a whole tranche of illness in children," she says.

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Adrian Hill, a vaccination expert at the Wellcome Trust Centre for Human Genetics at the University of Oxford, agrees: "It has been said it is the most cost-effective medical intervention full stop. There is nothing that has saved more lives at such a low cost."

Perhaps the damage has already been done with the MMR vaccine. But experts are debating how the government could avoid similar public conflict over vaccines in future.

Alaszewski says the government and doctors should emphasise that immunisation is in the interests of the whole population. He explains that parents who opt out of having their children vaccinated can benefit from what is known as "free-rider syndrome". The child who hasn't been vaccinated will be protected because most children have.

The difficulty occurs when vaccination rates fall below 80 or 90 per cent, allowing the disease to enter the population. "It is not about individual vaccination, it is about the level of vaccination in the country," he says.

As Heller explains: "We do things we don't want to do for the public good, and this is another example of individual choice versus public good."

But Rubery says such an argument is doomed to failure. She points to the scandal surrounding Labour MP Dianne Abbott's decision to send her son to a private school instead of a comprehensive. Abbott's personal motivation was more powerful than public or political arguments. "When it comes down to you and your family, your responsibility is to your child."

She says that ultimately people will agree to vaccination only if they genuinely believe that they - or their children - will be better off.

And winning over the public may not be the government's only challenge when it comes to controlling any new epidemic. Earlier this year an inquiry into infectious diseases conducted by the Lords science and technology committee concluded that the National Health Service might not be able to cope with any major outbreak.

Hill points out that while the UK is very strong in the area of immunology, no one is taking overall responsibility for the development of new vaccines. "There should be some body that has an oversight view to report to the government that no one is doing work on disease x and it should be prioritised," he says.

He feels that the Lords report succeeded in raising awareness of the issues surrounding infectious disease, but that little has changed since its publication.

Rubery hopes that if there were a sudden need for a mass influenza vaccination programme the government would have learnt from its problems with the MMR vaccine. But she says: "They can't avoid knowing that the MMR programme has gone wrong, yet there doesn't seem to be any indication that they are changing their policy."

And at the end of the day, perhaps the public can never be dictated to entirely. "If people want to die of influenza, that is their right," Rubery says.

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