Measles explosion threat in UK
Scientists predict massive outbreaks involving thousands of children in the near future unless more children are protected by vaccines.
The figures are the strongest warning yet of the negative effects of the unpopularity of the MMR triple vaccine among parents.
The number of unvaccinated children in towns across the UK mean that measles - a potentially fatal or disabling disease - is close to becoming permanently established in the community.
This would mean an end to isolated outbreaks of the virus, and the arrival of 'self-sustaining' disease in which children could catch it at any time.
Complex calculation
The latest study is published in the prestigious journal Science, and was authored by scientists at the Health Protection Agency and Royal Holloway College in London.
They have used a complex formula based on the number of unvaccinated children in a community, the average size of outbreaks and the age profile of the population to work out the risk of major outbreaks.
While there is also an element of chance involved, the results suggest that for the last four years, the UK has been hovering close to the point at which such huge outbreaks become likely.
Professor Vincent Jansen, a Wellcome Trust researcher from Royal Holloway College in London, and one of the researchers involved, said: 'We are now approaching the danger zone where measles could again become endemic in the UK.'
The change is reflected in the average size of a UK measles outbreak, which has increased from approximately 10 cases to 90 cases in recent years.
'We expect this trend to continue over the next four years if vaccine uptake does not increase.
'In the future the number affected by outbreaks may increase to 1,000.'
Deadly effect
In an outbreak of that size, it is likely that at least one child will die from the disease - a recent 3,000 case outbreak in the Netherlands claimed three lives.
A 1,600 case outbreak in the Irish Republic also killed three.
'Parents should be aware that there are risks associated with the decision not to vaccinate and those risks are increasing,' said Professor Jansen.
'My hope is that this study will provide a warning signal.'
While the vast majority of parents, even in the major cities, still choose to give their children MMR, more than one in seven in the UK does not receive the jab.
Vaccine shunned
The unpopularity of the vaccine follows suggestions from some scientists that the jab may be linked to autism and bowel disease.
However, no research has ever proved a link, and the overwhelming majority of experts believe the vaccine is safe.
An unvaccinated child living in a town with 95% MMR coverage - the government target - enjoys 'herd immunity' - protected to a great degree because vaccinated children around him or her cannot develop or pass on measles.
However, in a town where coverage falls below 80% - such as some parts of London, parents cannot rely on this protection.
Overall, the number of measles cases is still small compared with the days prior to vaccination, but it is rising.
Another study author, Dr Mary Ramsay from the Health Protection Agency, said: 'Many of these outbreaks are occurring in parts of the country where MMR uptake has dipped and been low for longer periods of time.
'We are concerned that if this pattern continues, the increasing number of unvaccinated people could lead to an increase in the number of susceptible children.
'This could lead to measles re-establishing itself as an endemic disease.'
Pojar pericol de explozie în Regatul Unit - Measles explosion threat in UK - articole medicale engleza - startsanatate