(FINANCIAL TIMES) - In the mid-17th century as Britain battled outbreaks of smallpox, plague and typhus, statistician John Graunt, widely viewed as the founder of epidemiology, sat poring over four decades of mortality records collected by parish clerks.
These "Bills of Mortality", he had realised by 1666, could be used to prove a simple idea: that epidemics ended not when the disease disappeared but when deaths returned to rates seen in normal times.
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