Scientific truth, and the vast benefits of modern medicine – which we take for granted at our peril – are under sustained attack from conspiracy theorists. Not since the nineteenth century has there been such a relentless assault on tried and tested science.

The promise of Robert F. Kennedy, the incoming Health Secretary in Donald Trump’s administration, to revoke the validation of the polio vaccine is a spectacular example of self-inflicted harm. The effective eradication of a terrible disease is under threat from a man who believes that vaccines – almost all vaccines – cause autism and other conditions, and that seed oils are a deadly threat to human health.

Tom Levenson’s brilliant, short historical book exposes the refusal of the anti-vax movement to accept the reality of communicable diseases and how to prevent them. Vaccines in earlier times provoked fear of the new and seemed to limit the liberty of individuals, but we are now dealing with historical amnesia on a grand scale: the anti-vaxxers have forgotten, or never knew, how terrifying life was with diseases like polio and mumps.