The modern myth that "vaccines cause autism" was started by the February 1998 publication of a study by Andrew Wakefield in The Lancet. According to The Sunday Times:
Confidential medical documents and interviews with witnesses have established that Andrew Wakefield manipulated patients’ data, which triggered fears that the MMR triple vaccine to protect against measles, mumps and rubella was linked to the condition.
The research was published in February 1998 in an article in The Lancet medical journal. It claimed that the families of eight out of 12 children attending a routine clinic at the hospital had blamed MMR for their autism, and said that problems came on within days of the jab.
The suggestion that there might be a link between vaccination and autism has resulted in a 12% drop in vaccination in the UK (from 92% to 80%), with an attendant 24x increase in confirmed measles cases in England and Wales (from 56 in 1998 to 1348 in 2008).
It turns out, however, that there appears to have been serious misconduct involved in the study's publication. Also from The Sunday Times:
However, our investigation, confirmed by evidence presented to the General Medical Council (GMC), reveals that: In most of the 12 cases, the children's ailments as described in The Lacent were different from their hospital and GP records. Although the research paper claimed that problems came on within days of the jab, in only one case did medical records suggest this was true, and in many of the cases medical concerns had been raised before the children were vaccinated.
There are also allegations that the children selected for the study were selected by, and the study paid for by, lawyers who were already pursuing litigation against vaccine companies.
What Wakefield seems to have done is not just dishonest -- he is apparently individually responsible for dropping the UK 15% below the threshold for total herd immunity (95%). If the allegations against him are true, he's personally responsible for thousands of cases of measles and some unknown numbers of deaths.
Any sensible person who knew the limitations of Wakefield's study would know that there was nothing to the alleged link between vaccination and autism: a single unblinded study of 12 individuals would be highly suspect even if the selection process wasn't subverted by lawyers. But thousands of parents have taken to heart the false idea that vaccination causes autism, and as a result thousands of children are unvaccinated, thousands have gotten measles, and undoubtedly some have died. Millions of dollars have been spent to disprove Wakefield's alleged "link".
Shame on you, Dr. Wakefield. You deserve everything that's coming at you.