LONDON -- A doctor whose research has been seized upon for the last five years by parents opposed to the measles, mumps, and rubella combined vaccine has urged them not to fear the childhood immunization, saying lingering concerns over a link with autism are unfounded.
In a letter published this week in The Lancet medical journal, Dr. Simon Murch warned that the proportion of toddlers getting the vaccine, known as MMR, has dropped so low in Britain that major measles outbreaks are likely this winter.
Measles has resurfaced in Britain recently in areas where MMR use has dropped; more children are getting infected every year.
The World Health Organization said Ireland, Spain, Italy, Germany, and Switzerland have also had recent outbreaks of measles and that declining MMR vaccination is likely a contributing factor.
"Although this situation reflects in part a broader mistrust of official pronouncements . . . it is founded on the misinformed perception that there is ongoing scientific uncertainty," said Murch, a pediatric gastroenterologist at the Royal Free Hospital in London.
"There is now unequivocal evidence that MMR is not a risk factor for autism -- this statement is not spin or medical conspiracy, but reflects an unprecedented volume of medical study on a worldwide basis," Murch said.
There has been no significant drop in MMR vaccination rates in the United States over the last eight years, according to the US Centers for Disease Control and Prevention.
Fears over the MMR vaccine intensified in Britain in 1998 after a study that Murch and others conducted raised the possibility of a connection between the vaccine and developmental problems in 12 children with bowel ailments. The study was done about eight years after the children had been vaccinated and involved parents being asked to recall whether symptoms of autism occurred around the same time as the vaccination.
Immunization rates in Britain and other countries began to fall after that. The national rate in Britain has slipped from 91.7 percent in 1997 to 78.9 percent in June of this year, well below the 90 to 95 percent specialists say is needed.