In the Seventies there was a similar outcry against the whooping cough, or pertussis, vaccine. Uptake fell drastically, from 80 per cent to only 30 per cent of children, as a result. Since then, there have been concerted efforts to promote the vaccine, resulting in a record uptake of 93 per cent today. But research from this country and America is about to reawaken the disquiet.
This time the perceived problems are not with the drastic short-term effects of the jab (fear that the vaccine triggers brain damage in a tiny minority of susceptible children), but its long-term impact.
A British survey into child health, published last year, has found a statistical link between the pertussis vaccine and childhood asthma. The team from the Primal Health Research Centre in London traced 446 children, many via the breast-feeding support organisation La Leche League, who were fully breast-fed for six months and still breast-feeding at one year old. The aim was to identify the conditions and criteria for long-term health in what was an ideally homogenous group.
Dr Michel Odent, the French surgeon and researcher who founded the research centre and who is a pioneer of natural birth, found that 243 children and adolescents had been immunised against whooping cough and 203 had not. The results, summarised in the Journal of the American Medical Association, demonstrated that a child who received the pertussis vaccine was 5.43 times more likely to suffer from asthma.
The survey also showed that a pertussis-vaccinated child was twice as likely to suffer from ear infections as a child who had not received the vaccine, was more likely to suffer from a range of other diseases, and more likely to be hospitalised and for longer periods.
"The medical establishment has been very honest when discussing how effective vaccines are," says Dr Odent. "Also, the short-term side-effects have been seriously studied and documented. But it's very difficult to find information on the long-term medical effects, and this is something for future study."
Dr Odent draws attention to the importance of vaccination in what he calls the "primal period" - the months spanning foetal life and early infancy.
"It is during the primal period that the adaptive systems involved in what we commonly call health reach maturity," says Dr Odent. "It is the time of close dependence on the mother. One can anticipate that any kind of event happening during this period can have irreversible effects.
"I don't want to present myself as someone who is against vaccination. But we hope our data will be helpful at a time when clinical studies are in progress for a new whooping cough vaccine."
The conventional "whole cell" vaccine against whooping cough was introduced in the Fifties and continues to be used today. Twenty years ago, it was postulated that the vaccine was responsible for the onset of brain disorder in one out of 310,000 children. Intensive studies have since suggested that brain damage would have occurred anyway in susceptible children, given a certain kind of trigger.
Nevertheless, America's Institute of Medicine, National Academy of Science (USA) found a causal link between the "triple" diphtheria-tetanus-pertussis (DTP) vaccine and certain acute conditions, such as allergic attacks and long periods of inconsolable screaming in babies. As a result of these scares, scientists started searching for a vaccine that might be more acceptable to the public, and their efforts are slowly coming to fruition. The development of an acellular vaccine - which isolates the useful molecules from the cell and should reduce the risk of side-effects - is under way in Japan, America and Sweden.
But the new vaccine technology has so far proved fully effective only in mice, and until similar success is achieved with humans, public health professionals continue to place their confidence in the old-style vaccine.
Meanwhile, further evidence from two American cities suggests that the pertussis vaccine may simply not be as effective as was once thought.
In Massachusetts, 94 per cent of children are vaccinated from the age of three months. An uptake as high as this ought to be enough virtually to eliminate the disease, yet 435 cases of whooping cough were unexpectedly diagnosed between 1981 and 1991. In Cincinatti during 1993, 223 children between six months and six years old were diagnosed with whooping cough, despite the fact that 82 per cent of these had been fully vaccinated.
As well as apparent outbreaks of genuine pertussis, doctors have identified a condition known as "pseudo whooping cough", which occurs in vaccinated subjects who suffer the characteristic "whoop" for up to three weeks. The vaccine cannot protect against this copycat disease. Parents are bewildered when vaccinated children start whooping and occasionally suffer even more than friends or siblings who were not immunised.
Dr Noel Preston, former director of the Pertussis Reference Laboratory in Manchester, is keen to calm the waters. "There's good evidence that most of the vaccines we use at the present time are capable of eradicating disease," he says. "The chances are that we will have eliminated pertussis before an acellular vaccine is developed.
"Looking at Dr Odent's study, I would like to ask: what were the symptoms of asthma and who made the diagnosis? Are we in fact dealing with a single defined entity? I would also wonder about the reliability of the parental recall of vaccination. During the Seventies and Eighties when I was involved in the enormous outbreaks of whooping cough which followed the scares about the vaccine, I came across dozens of cases when parents inaccurately recalled that their children had been vaccinated.
"There is always a danger in a retrospective study, and the authors themselves admit the need for further research. We should ask: does it sound reasonable? For instance, did the incidence of asthma fall during the Eighties when uptake of pertussis vaccine was low?
"Why should we imagine all this possible evil when there's no evidence at all? Until we produce some evidence, why go around trying to scare people?"
Dr Odent is aware of the need for further research but is confident that his survey poses some significant and previously unasked questions. "This is a large study of children who were all breast-fed for more than a year, a very homogenous group," he says. "The advantage of a control study like this is that we can reduce the effects of confounding factors such as those suggested by Dr Preston.
"Ours is a retrospective study because this is the material at our disposal at the moment. I wonder why there have never been prospective studies done before."
Dr Odent also has some questions he would like to see addressed. "We have to ask, why has asthma been increasing dramatically in the past 30 years? Researchers are now saying that air pollution is not the cause. They call it the 'hidden epidemic'.
"People have to consider the whooping cough vaccine very carefully."