Did the MMR vaccine cause autism? How the Wakefield claim was debunked

No. The measles, mumps and rubella (MMR) vaccine does not cause autism. The idea traces back to a 1998 paper in The Lancet, led by Andrew Wakefield, that reported on twelve children and raised the possibility of a link between a bowel disease, autism and the MMR vaccine. That paper was later retracted, and extensive investigation has found no relationship between vaccines and autism, causal or otherwise.

The paper itself said no causal connection had been proven, but Wakefield called at a press conference for the triple vaccine to be suspended. In 2004 the journalist Brian Deer reported that some of the twelve children had been recruited via a lawyer preparing a lawsuit against vaccine manufacturers. His main claim, that he found measles virus material in the children's intestines, was later shown to be due to errors at the laboratory that ran the tests. In 2010 the UK General Medical Council found Wakefield had been dishonest in his research, and The Lancet fully retracted the paper.

Meanwhile, bigger studies went looking. The CDC, the US Institute of Medicine and the NHS concluded there is no link, a Cochrane review found no credible link, and in 2019 a Danish study following more than 650,000 children for over ten years found no link, even among children with autistic siblings. Reported autism incidence in the UK had started rising before MMR was introduced in 1989.

The publicity is reported to have caused a sharp fall in vaccination uptake, followed by measles outbreaks and many deaths. The story is a lesson in how one small, flawed study can travel further than the large studies that correct it.