The scandal over the supposed link between the measles, mumps and rubella (MMR) vaccine and autism is one of the worst health scares in living memory. Hundreds of thousands of parents rejected one of the most fundamental safeguards for children on the basis of a false alarm. Today, it’s what we would call “fake news”.

Measles, a highly unpleasant disease which can lead to life-threatening infections of the lungs and brain, had been virtually eliminated in Britain following the introduction of MMR in 1988. Just decades before that, up to half a million children were infected every year, and about 100 died. Even in 1988, there were 80,000 cases, with 16 deaths.

Within just 10 years of MMR’s introduction, however, rates of infection were plummeting towards zero. But then a highly successful public health campaign was derailed. After the vaccine scare, the disease made a comeback, with more than 2,000 cases confirmed in 2012. Small children who had not been given either the initial MMR jab (usually at about one year old) or the usual supplementary jab – or both – found themselves at risk. By 2006, in London, almost half of five-year-olds had not received both jabs.