Wakefield also failed to disclose he was paid in conjunction with the lawsuit, or that he had a patent related to a new MMR vaccine in development when he submitted the case report for publication.
Moreover, according to one of the findings against the doctor, Wakefield took blood samples from children at his own child's birthday party and paid them each five British pounds for their trouble.
Following the GMC's Jan. 28 ruling, Wakefield declined an interview with ABCNews.com, but issued a statement saying, "The allegations against me and against my colleagues are both unfounded and unjust and I invite anyone to examine the contents of these proceedings and come to their own conclusion."
The GMC ruling is unlikely to erase the apparently false connection between vaccines and autism from the public mind. Nor will it detract from Wakefield's positive reputation among some activists groups.
Following the GMC's decision, the advocacy group the Autism Society issued a statement in which it said it "strongly supports funding research into gastrointestinal pathology, as well as any links between this pathology and the symptoms of autism. ... In this field, Dr. Wakefield's contributions to our families and members are greatly appreciated and there are many who support him in his research efforts."
Similarly, the parent groups who stood behind Wakefield in rallies and in press statements say his theories have led to anecdotally successful treatment in their children and also doubt that a finding by the GMC will change any minds.
It is on this point that critics of Wakefield's work agree.
"In some ways I think [the GMC ruling] is irrelevant," said Dr. Paul Offit, chief of the Section of Infectious Diseases at Children's Hospital of Philadelphia, who has been twice threatened with lawsuits for critical statements he has made of Wakefield's work.
According to Offit -- and international studies supported by the CDC as well as a 2004 review of large international studies by the Institute of Medicine -- high-quality studies could not confirm Wakefield's hypothesis about vaccines.
Still, when the public got word of Wakefield's work, worried parents skipped vaccines, and the percentage of children who were not vaccinated in the United States rose from 0.77 percent in 1997 to 2.1 percent in 2000, according to an article by Dr. Michael Smith in the journal Pediatrics. A similar rise in children not being vaccinated occurred in Britain.
Although the U.S. Centers for Disease Control declared the United States cleared of measles in 2000, the lower vaccination rate brought back the disease in a 2008 outbreak. At least 131 cases were reported to the CDC, and 11 percent of the cases were hospitalized. A handful of children in Britain died of the measles around the time of the U.S. outbreak.
Since the publication of the 1998 article, Wakefield has left England and has set up an alternative research and treatment organization called Thoughtful House in Austin, Texas. On April 7, the GMC is scheduled to decide whether his ethical breaches constitute "serious professional misconduct" and if so, how Wakefield will be reprimanded or whether he will lose his license.
Regardless of the outcome, many vaccine efforts hope that this latest chapter in the debate over a connection between vaccines and autism will be the last.