It took nearly six months but the General Medical Council (GMC) in the U.K. has pulled Dr. Andrew Wakefield’s license to practice medicine in the United Kingdom.

Wakefield is the researcher who nearly single-handedly fueled parental concerns about the link between vaccines and autism. In 1998, he published a paper in the medical journal Lancet describing eight children who showed signs of autism within days of being inoculated for measles, mumps and rubella. A gastroenterologist by training, Wakefield went on in further studies to suggest that the virus from the vaccine was leading to inflammation in the youngsters’ guts that then impeded normal brain development.

Further investigations by other researchers in the decades since have failed to confirm his claims, and in January, the GMC ruled that Wakefield had acted “dishonestly and irresponsibly” in conducting the experiments that led to the publication of the paper. According to the BBC, among his alleged acts of misconduct were conducting those studies without ethical approval of the hospital at which he practiced, and paying children at his son’s birthday party for blood samples. He also served as a paid consultant to attorneys of parents who believed their children had been harmed by vaccines.

In February, editors of the Lancet retracted Wakefield’s controversial paper, telling the Guardian “It was utterly clear, without any ambiguity at all, that the statements in the paper were utterly false.”

Defending his career on the Today show on Monday, Wakefield, now in the U.S., vowed to appeal the decision and maintained that “there are millions of children out there suffering, and the fact [is] that the vaccines cause autism.” Without a license to practice medicine, and the growing evidence to the contrary, it’s going to harder for him to prove that claim.