The outbreak’s ferocity and lethality is still frightening.
In less than two weeks, cholera killed nearly 700 people in a London neighborhood. Of the 45 houses near the epicenter of the epidemic, 41 lost at least one inhabitant.
It was September 1854. Faced with a fast-spreading killer bacterium, the people of Broad Street did not have advanced medical technology, trained epidemiologists or the concept of oral rehydration therapy. They had John Snow, a physician and pioneering anesthetist with a gift for analyzing data. Snow’s forceful plea to the St. James Parish Board of Governors for the removal of the Broad Street pump remains an iconic moment in the history of public health. However, it never would have happened had it not been for his particularly stubborn opposition to the status quo.
Since cholera’s arrival on England’s shores in 1832, it was commonly accepted that the disease was caused by miasma—poisonous air. As author Steven Johnson explains in The Ghost Map, his terrific history of the 1854 cholera outbreak, medical and political leaders blamed the inner city’s noxious air for cholera’s spread. London’s legendary demographer William Farr even found evidence supporting the miasma theory. By mapping cholera deaths by elevation, he found a correlation between higher elevations (with presumably cleaner air) and reduced risk for cholera death. But as any public health student will tell you, correlation does not causation make.
Almost a year after the removal of the pump handle and the taming of the cholera outbreak on Broad Street, an unsigned editorial in The Lancet’s June 23, 1855, issue attacked Snow and his theory: “In riding his hobby very hard, he has fallen down through a gully-hole and has never since been able to get out again.” It took Snow’s uncommon stubbornness to knock down the miasma theory and build the case for waterborne contamination. However, it would be long after Snow’s death in 1858 before his theory was accepted as fact.
John Snow, meet Sabra Klein.
As the cover story in this spring issue attests, Klein has spent her share of time in the scientific wilderness. She firmly believes that whether you’re male or female has a great influence on how your body responds to everything from influenza to depression. For years, scientists with influence and status have told her flat out that sex does not matter. Klein, who confesses to not being “born with a thick skin,” may have taken their criticisms personally but she has persevered because she believes the evidence is leading her somewhere important. In a New York Times op-ed written during the 2009 H1N1 epidemic, Klein argued that because women have a stronger immune system than men, they do not require as large of a dose of flu vaccine.
The op-ed and more importantly the mounds of data on sex-based biology that she and others have been accumulating are beginning to get traction. Scientists who previously denied the importance of sex differences are now sharing data with Klein and report seeing trends of their own. The research literature is still ignoring the issue for the most part, but Klein vows, “The book is not closed, the story not over.”
Science, which depends on the slow accumulation of data, is such an interesting endeavor because it’s such a human activity. It embodies our great strengths and weaknesses, unleashing illuminating sparks of intuition, and, at times, small-mindedness that clouds reality. “How could so many intelligent people be so grievously wrong for such an extended period of time?” asks Johnson early in The Ghost Map.
Part of the answer is that new ideas are dangerous. They disrupt our foundational assumptions. Humans, on the whole, don’t like that. We find security in the familiar, support in agreement with others and comfort in “knowing” things to be true. Scientists, like anyone, can easily slip into groupthink, their ideas corralled by the herd.
At the same time, we relish stories like those of Snow and Klein. We like the underdog, the individual who stands against others and forces disruptive yet positive change.
Science does change. It just requires equal parts evidence and stubbornness.