Among the most shocking sights at Donald Trump’s inauguration ball in 2017 was the presence of Andrew Wakefield. The disgraced former doctor was struck off the medical register in 2010 following what was deemed an unreliable study linking the MMR (measles, mumps and rubella) vaccine to autism.

Many have dismissed Wakefield’s work as “fake science” and multiple independent studies have proved him wrong. But this hasn’t stopped millions embracing his theories, Trump included. Wakefield now makes a living as a figurehead of the US “anti-vax” movement. Anti-vaxxers aren’t confined to one ideology: liberal hippies as well as Tea Party conservatives denounce vaccines as harmful.

The rise of the anti-vax movement is resulting in an alarming surge in cases of measles across the globe – more than 1,100 have been reported in England this year. Some anti-vaxxers believe that by injecting live, albeit “attenuated”, viruses into people, you expose them to harm.

Others, including JFK’s nephew, Robert F Kennedy Jr, a prominent liberal anti-vaxxer, hold that the dangers of vaccines arise from the mercury-containing thimerosal used in some preparations.

As thimerosal hasn’t been added to most child vaccines for more than 18 years, while autism levels have continued to rise, that theory is bogus. Yet with trust in science and the mainstream media rapidly declining, the anti-vaxxers have spied an opening.

The English physician Edward Jenner invented vaccination in 1796. He knew that milkmaids, whose hands were frequently pustular with cowpox, seldom caught smallpox, which then afflicted millions around the globe. Jenner took pus from a cowpox sore and injected it into James Phipps, his gardener’s eight-year-old son. Phipps was later injected with material from a smallpox lesion and failed to develop the disease. Jenner repeated the experiment on others, reproducing the protective effect.

The great French scientist Louis Pasteur coined the term “vaccination” in honour of Jenner’s work (vacca being the Latin for cow).

Vaccines work by stimulating our immune systems to recognise a pathogen without exposing us to the disease-causing bacterium or virus itself. The immune system provoked by the cowpox virus also recognises and neutralises its smallpox relative. The same concept applies to other vaccines. In the case of measles, mumps and rubella, weakened but still living forms of the viruses prime our immune systems to kill the real thing, should we become infected.

Although never a major killer in the prosperous Western world, where otherwise healthy and well-nourished people can combat the disease, measles has been a scourge in developing countries. As recently as the turn of the 21st century, nearly a million people died from measles each year. That number has fallen dramatically: there were fewer than 90,000 measles deaths globally in 2016. Vaccination has been at the core of this remarkable progress.

Last year, however, Europe bucked the downward trend. There was a four-fold increase on the previous year with 21,315 measles cases, including 35 deaths. Worst afflicted was Romania, where the Roma populations, who eschew vaccination, were hardest hit. The US, where the anti-vax movement is gaining ground, also risks losing its freedom from endemic measles.

Vaccines can eradicate disease. Smallpox, which once killed millions every year, has not been with us since the 1970s thanks to a global vaccination campaign.

Once a critical number of people are vaccinated, insufficient numbers of vulnerable targets remain for the virus to infect. It declines to extinction. For measles that number is around 95 per cent. Parents exempting their children from vaccination aren’t merely putting their offspring at risk – they are maintaining the environment in which pathogens persist. We could have eliminated measles from Europe by now and brought global levels lower still. Fake science kills.

Michael Barrett is professor of biochemical parasitology at the University of Glasgow