An introduction to the history of infectious diseases, epidemics and the early phases of the long-run decline in mortality.

This article, written during the COVID-19 epidemic, provides a general introduction to the long-term history of infectious diseases, epidemics and the early phases of the spectacular long-term improvements in life expectancy since 1750, primarily with reference to English history. The story is a fundamentally optimistic one. In 2019 global life expectancy was approaching 73 years. In 1800 it was probably about 30. To understand the origins of this transition, we have to look at the historical sequence by which so many causes of premature death have been vanquished over time. In England that story begins much earlier than often supposed, in the years around 1600. The first two 'victories' were over famine and plague. However, economic changes with negative influences on mortality meant that, despite this, life expectancies were either falling or stable between the late sixteenth and mid eighteenth centuries. The late eighteenth and early nineteenth century saw major declines in deaths from smallpox, malaria and typhus and the beginnings of the long-run increases in life expectancy. The period also saw urban areas become capable of demographic growth without a constant stream of migrants from the countryside: a necessary precondition for the global urbanization of the last two centuries and for modern economic growth. Since 1840 the highest national life expectancy globally has increased by three years in every decade.