The surveillance society we need: An interview with Prabhat Jha
“Imagine if Zika had come to New York or to Toronto,” says Prabhat Jha from his office at the St. Michael’s Hospital Center for Global Health Research in Toronto. Yes, there would be media panic, but behind the headlines there would also be something far more useful: reasonably sound baseline health data. That kind of detailed measurement would be able to show us the prevalence of microcephaly—a brain defect in babies—in the population of each city, so that any new cause for the condition could be spotted and understood. Instead, Zika emerged in Brazil, where surveillance systems have been ravaged by budget cuts—and whose diagnostic criteria for microcephaly in newborns are problematic.
It is as a tireless advocate for collecting such data that Jha has been recognized as one of the most influential contemporary figures in public health. He is the lead investigator on the decade-long Million Death Study (MDS) in India, a simple yet revelatory attempt to find out exactly how ordinary Indians die, given that so few of them die in hospital or with the kind of medical attention that could capture the causes of their mortality.
What the world needs, he says, are “vigorous routine surveillance systems,” similar in scope to those in finance. “The world and the IMF [International Monetary Fund] and others have gotten pretty good about estimating or getting reasonably real time information on financial flows and disturbances in the market that might portend big changes in macroeconomic policy.” But, he says, those systems didn’t just spontaneously occur. In the 1960s, the IMF invested in reporting systems for every country that had national accounts. “They used a combination of tough love and technical support to say, ‘You’ve got to have these systems,’ and now they’re the basis for how the world economies work.”
It is, he says, “astonishing” that we haven’t created a similar global system to monitor mortality, and infectious disease and its vectors, such as the Aedes aegypti mosquito, whose increasing distribution around the globe has driven the spread of Dengue fever. It is even more astonishing that we learned the importance of collecting this kind of data 140 years ago. “You start with extremely simple principles that, actually, were laid out in 1869,” he says. “The Sanitary Commissioner of India wrote, ‘for sanitary purposes it is indispensable to know the relative mortality in small, and as far as possible, well-defined tracts to ascertain the death rates in these communities and to apply the remedies.’”
In the 19th century, the collection and analysis of such “vital statistics” as mortality was central to the emerging idea and practice of public health—and the impact, whether of Lemuel Shattuck’s sanitary survey of Massachusetts or Florence Nightingale’s analysis of British military deaths in the Crimea was transformative. Shattuck, who founded the American Statistical Association, used statistical evidence to formulate 50 recommendations essential to creating a public health infrastructure in the United States, most of which are still common practice; Nightingale created powerful data visualizations to show politicians how improving hygiene could have saved many soldiers’ lives, given that sickness claimed many more lives in the Crimea than combat wounds. These insights, in turn, led her to consider the role of hygiene in the British Army in India, and then hygiene in India’s population at large, all of which, she stressed, could only be assessed and addressed by the careful collection of data.
There is a direct line between those 19th century dreams of big data and the Million Death Study, which took place in two phases between 1997 and 2014. Over 2.4 million households were visited and deaths were recorded using a method called verbal autopsy. As Jha, puts it, you don’t know what you’re looking for until you actually look—and, in this case, the data revealed that malaria was killing a lot more people than had been assumed, while HIV was killing fewer people. (Nature published an excellent overview in 2013 of the study results to date).
Jha estimates that it would take $20 to $30-billion dollars to create the systems for every country to count its dead and conduct basic surveillance for the dramatic infectious diseases but also the more routine, yet larger toll from chronic diseases. The amount is trivial next to the economic losses of not knowing what people are dying from, especially in an era of emerging global pandemics.
“We should not let good crises go to waste. This is the third surveillance crises in recent years, and should spur us to push for a massive increase in disease surveillance across all countries. I mean, that would seem obvious, wouldn’t it?” he says. “If the Zika crisis was used to build a sustainable system for this kind of surveillance, then we would be much better prepared in the future.”