How do pandemics end? In different ways, but it’s never quick and never neat

On 7 September 1854, in the middle of a raging cholera epidemic, the physician John Snow approached the board of guardians of St James’s parish for permission to remove the handle from a public water pump in Broad Street in London’s Soho. Snow observed that 61 victims of the cholera had recently drawn water from the pump and reasoned that contaminated water was the source of the epidemic. His request was granted and, even though it would take a further 30 years for the germ theory of cholera to become accepted, his action ended the epidemic.

text: Photograph: Print Collector/Getty Images

© Provided by The Guardian
Photograph: Print Collector/Getty Images

As we adjust to another round of coronavirus restrictions, it would be nice to think that Boris Johnson and Matt Hancock have a similar endpoint in sight for Covid-19. Unfortunately, history suggests that epidemics rarely have such neat endings as the 1854 cholera epidemic. Quite the opposite: as the social historian of medicine Charles Rosenberg observed, most epidemics “drift towards closure”. It is 40 years since the identification of the first Aids cases, for instance, yet every year 1.7 million people are infected with HIV. Indeed, in the absence of a vaccine, the World Health Organization does not expect to call time on it before 2030.

However, while HIV continues to pose a biological threat, it does not inspire anything like the same fears as it did in the early 1980s when the Thatcher government launched its “Don’t Die of Ignorance” campaign, replete with scary images of falling tombstones. Indeed, from a psychological standpoint, we can say that the Aids pandemic ended with the development of antiretroviral drugs and the discovery that patients infected with HIV could live with the virus well into old age.

The Great Barrington declaration, advocating the controlled spread of coronavirus in younger age groups alongside the sheltering of the elderly, taps into a similar desire to banish the fear of Covid-19 and bring narrative closure to this pandemic. Implicit in the declaration signed by scientists at Harvard and other institutions is the idea that pandemics are as much social as biological phenomena and that if we were willing to accept higher levels of infection and death we would reach herd immunity quicker and return to normality sooner.

But other scientists, writing in the Lancet, say the Great Barrington strategy rests on a “dangerous fallacy”. There is no evidence for lasting “herd immunity” to the coronavirus following natural infection. Rather than ending the pandemic, they argue, uncontrolled transmission in younger people could merely result in recurrent epidemics, as was the case with numerous infectious diseases before the advent of vaccines.

‘Water! Water! Everywhere; and not a Drop to Drink’: Another Punch cartoon, this one on the London outbreak of 1849. Photograph: Print Collector/Getty Images

© Provided by The Guardian
‘Water! Water! Everywhere; and not a Drop to Drink’: Another Punch cartoon, this one on the London outbreak of 1849. Photograph: Print Collector/Getty Images

It is no coincidence they have called their rival petition “the John Snow memorandum”. Snow’s decisive action in Soho may have ended the 1854 epidemic, but cholera returned in 1866 and

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