A doctor who persuaded millions of parents worldwide that a common vaccine could cause autism, has been barred from practicing medicine in his native Britain.
The country's top medical group has found he conducted his research unethically.
Dr Andrew Wakefield was the first researcher to publish a peer-reviewed study suggesting a connection between autism and the vaccine for measles, mumps and rubella.
That prompted legions of parents to abandon the vaccine in moves that epidemiologists feared could lead to outbreaks of the potentially deadly diseases.
Vaccination rates in Britain and other rich countries have not fully recovered since Wakefield and his colleagues' research was published in 1998 and there are measles outbreaks across Europe every year.
There are also sporadic outbreaks of the disease in the US.
His study in the medical journal Lancet was widely discredited, however, after Britain's medical regulator found it did not meet ethical standards; other studies found no link; and a British journalist revealed Wakefield had been paid by lawyers of parents who suspected their children were harmed by the vaccine.
Wakefield, 53, moved to the US in 2004 and set up an autism centre in Texas, where he gained a wide following despite not being licenced as a doctor there, and faced similar scepticism from the medical community. He quit earlier this year.
Britain's General Medical Council was acting Monday on a January ruling that said Wakefield and two other doctors acted unethically and showed a "callous disregard" for the children in their study.
The medical body said Wakefield took blood samples from children at his son's birthday party, paying them 5 pounds (NZ$11) each and later joked about the incident.
The council, which licenses and oversees doctors, found him guilty of serious professional misconduct and stripped him of his right to practice medicine in the UK.
Wakefield said he plans to appeal the ruling, which takes effect within 28 days. The investigation focused on how Wakefield and colleagues carried out their research, not on the science behind it.
Wakefield said in January that the medical council's investigation was an effort to "discredit and silence" him to "shield the government from exposure on the (measles) vaccine scandal."
Appearing from New York on NBC's Today Show on Monday, Wakefield described the British decision as "a little bump on the road." He claimed the US government has been settling cases of vaccine-induced autism since 1991.
Wakefield said the council's ruling against him had been "made from the outset" and vowed to continue his research into the link between vaccines and autism.
"These parents are not going away; the children are not going to go away and I most certainly am not going away," he said.
Numerous studies have been conducted since Wakefield's and none has found a connection between autism and any vaccine.
Two rulings by a special branch of the US Court of Federal Claims in March and last year found no link between vaccines and autism. But more than 5500 claims have been filed by families seeking compensation for children believed to have been hurt by the measles vaccine.
Wakefield has garnered much support from parents suspicious of vaccines, including some Hollywood celebrities. In February, US actress Jenny McCarthy, who has an autistic son, issued a statement with her former partner Jim Carrey.
"It is our most sincere belief that Dr Wakefield and parents of children with autism around the world are being subjected to a remarkable media campaign engineered by vaccine manufacturers," McCarthy and Carrey said in February. "Dr Wakefield is being vilified through a well-orchestrated smear campaign."
In Monday's ruling, the medical council said Wakefield abused his position as a doctor and "brought the medical profession into disrepute."
At the time, Wakefield was working as a gastroenterologist at London's Royal Free Hospital and did not have the ethical approval to conduct the study.
The study suggested autistic children had a new bowel disease and raised the possibility of a link between autism and vaccines. He had also been paid to advise lawyers representing parents who believed their children had been hurt by the measles, mumps and rubella vaccine.
Ten of the study's authors later renounced its conclusions and it was retracted by the Lancet in February.
At least a dozen British medical associations including the Royal College of Physicians, the Medical Research Council and the Wellcome Trust have issued statements verifying the safety of the measles, mumps and rubella vaccine.
This verdict is not about (the measles) vaccine," said Adam Finn, a professor of pediatrics at the University of Bristol Medical School. "We all now know that the vaccine is remarkably safe and enormously effective...we badly need to put this right for the sake of our own children and children worldwide."