28 February 1998 Gastroenterologist Andrew Wakefield reports in The Lancet that his team has found a “genuinely new syndrome”—a link between the measles, mumps and rubella (MMR) vaccine and an increased risk of autism (Lancet 351, 637–641, 1998).

6 April 2000 Wakefield and Dublin pathologist John O'Leary present research to a US congressional committee showing that 24 of 25 autistic children tested had traces of the measles virus in their gut.

2002–2004 Numerous studies published in BMJ, The New England Journal of Medicine, The Lancet and other journals find no link between MMR and autism.

6 March 2004 Ten authors on the 1998 paper issue a retraction (Lancet 363, 750, 2004), and The Lancet's editor says the journal, in hindsight, should not have published the study (Lancet 363, 747–749, 2004).

28 January 2010 The UK General Medical Council rules that Wakefield acted “dishonestly and irresponsibly,” and showed “callous disregard” for the suffering of children involved in his controversial research.

2 February 2010 The Lancet retracts Wakefield's 1998 paper, noting elements of the manuscript proved to be false (Lancet doi:10.1016/S0140-6736(10)60175-7, 2010).