The Rules of Contagion

rise and fall of epidemics as far as we can see at present can be
explained by the general laws of happenings,’ they suggested.[61]
Unfortunately, Hudson and Ross’s work on the Theory of
Happenings would be limited to three papers. One barrier was the
First World War. In 1916, Hudson was called away to help design
aircraft as part of the British war effort, work for which she would later
get an OBE.[62] After the war, they faced another hurdle, with the
papers ignored by their target audience. ‘So little interest was taken in
them by the “health authorities,” that I have thought it useless to
continue,’ Ross later wrote.
When Ross first started working on the Theory of Happenings,
he’d hoped it could eventually tackle ‘questions connected with
statistics, demography, public health, the theory of evolution, and
even commerce, politics and statesmanship’.[63] It was a grand
vision, and one that would eventually transform how we think about
contagion. Yet even in the field of infectious disease research, several
decades would pass before the methods became popular. And it
would take even longer for the ideas to make their way into other
areas of life.