A major Japanese study should dispel lingering fears from a 12-year-old scare that a multiple vaccine against measles, mumps and rubella (MMR) is to blame for a rise in autism, the British weekly New Scientist says.
The panic, unleashed in 1998, prompted tens of thousands of British parents to refuse the vaccine for their children.
However, several big studies have failed to found any link between the vaccine and autism. Exactly a year ago, 10 of the 13 British doctors who authored the original research in The Lancet medical weekly retracted their findings.
A study into 31,426 children in the Japanese city of Yokohama “should put the final nail in the coffin” of the scare, New Scientist says in next Saturday’s issue.
Japan used the MMR vaccine for a number of years before withdrawing it in April 1993, responding to reports that the anti-mumps components may cause meningitis.
Hideo Honda of the Yokohama Rehabilitation Centre looked at children born between 1988 and 1996, a period that straddles the withdrawal date.
The number of children diagnosed as autistic after the age of seven continued to rise after the vaccine had been withdrawn, he found.
In the years before 1993, incidence of autism ranged from 48 to 86 cases per 10,000 children. But after 1993, it rose, with cases ranging from 97 to 161 per 10,000.
The study cannot rule out the possibility that MMR may trigger autism in a very small number of children. However, it confirms that there is no large-scale effect.
Honda’s research appears in full in the Journal of Child Psychology and Psychiatry.
Scientists are divided about why autism appears to be rising in developed countries.
Some say there may be an environmental cause; others say that cases of autism are more likely to be detected and reported because the taboo surrounding this condition is receding.
The MMR scare was overwhelmingly centered on Britain. In some parts of that country, the proportion of children getting the vaccination has slumped to 60 percent, triggering outbreaks of measles, says New Scientist.