People have been misled by media reports that the measles, mumps and rubella vaccine could be unsafe, according to new research.
Most people thought medical opinion on MMR was evenly divided
A survey by Cardiff University claims that more than half of the British public wrongly believe that medical science opinion was split down the middle on the subject.
But in fact almost all scientific experts rejected the claim of a link between the measles, mumps and rubella (MMR) vaccine and autism, said the research.
The study was carried out after publicity given to concerns raised by Dr Andrew Wakefield about the injection.
There were also allegations that it could be linked to inflammatory bowel disease, and led to vaccination rates falling.
Researchers in Cardiff have examined the way that the MMR vaccine was reported by print and broadcast media.
Staff at the School of Journalism, Media and Cultural Studies also looked at the public's knowledge of these issues.
Research questioning the safety of something that is widely used should be approached with caution
Professor Justin Lewis, one of the authors of the survey, said: "The survey confirms that the news media play a key role in informing the way people understand issues such as the controversy around MMR.
"While Wakefield's claims are of legitimate public interest, our report shows that research questioning the safety of something that is widely used should be approached with caution, both by scientists and journalists," he said.
Dr Andrew Wakefield claimed the MMR vaccine could cause autism
The report found that 53% of those surveyed at the height of the media coverage assumed that because both sides of the debate received equal coverage, there must be equal evidence for each.
It said only 23% were aware that the bulk of evidence favoured supporters of the vaccine.
The authors said their survey would revive the debate about media coverage of MMR and how journalists deal with "minority voices" within science.
The report, done with funding from the Economic and Social Research Council, said: "Attempts to balance claim about the risks of the MMR jab tended merely to indicate that there were two competing bodies of evidence."
Some 48% of people surveyed felt that on matters of public health, journalists should wait until other studies confirmed findings before reporting alarming research.
But 34% said that concerns like those of Dr Wakefield's were newsworthy and should be reported.
Prof Lewis said any decline in confidence could have serious consequences for public health.
"The research also has implications for the debate about fairness in journalism, suggesting that legal definitions of impartiality in broadcast journalism should not be interpreted in a simplistic fashion," he added.
The research was carried out between January and September 2002 and involved two surveys of more than 1,000 people and an analysis of 2,214 newspaper, radio and TV stories.