335 new diseases emerged between 1960 and 2004. Why weren’t we ready for this one?
The following article was written by Frank Snowden, Andrew Downey Orrick Professor Emeritus of History and History of Medicine, and appears in The Yale Review.
As the novel coronavirus spiraled out of control on three continents and within the United States—which would quickly become the nation with the most confirmed cases—the American president asked, “Who would have thought?” But like all pandemics, COVID-19 is not an accidental or random event.
Epidemics afflict societies through the specific vulnerabilities we have created in our relationships with the environment, other species, and each other. The microbes that ignite pandemics have adapted to fill the ecological niches that we have prepared. COVID-19 flared up and spread because it is suited to the society we have made. A world with nearly eight billion people, the majority of whom live in densely crowded cities and all linked by rapid air travel, creates innumerable opportunities for pulmonary viruses. At the same time, demographic increase and frenetic urbanization have led to the invasion and destruction of animal habitat, altering the relationship of humans to the animal world. Particularly relevant is the resulting multiplication of contacts with bats, which are a natural reservoir of innumerable viruses capable of crossing the species barrier and spilling over to humans.
Such spillovers occur with growing frequency—usually without widespread consequences. But contingent circumstances may favor transmission from a first human host to others, as Ebola demonstrated in December 2013. At that time, a small child played in the hollow of a tree near the garden of his home in Guinea. Rampant deforestation there had led fruit bats—evicted from the demolished canopy of the nearby woods—to cluster by the thousands. The misfortune of the four-year-old boy was to inhale viruses shed in the dejecta of the displaced bats. All of the subsequent victims of Ebola throughout the West African epidemic of 2014–2016 were linked in an unbroken chain of transmission from this first, or “index,” case.
This sequence of events, transposed to an urban context, probably recurred in December 2019 at a bushmeat “wet market” in Wuhan, China. There a combination of factors transformed a warren of closely packed stalls lacking refrigeration and narrow, unhygienic passageways into a giant petri dish. The major conditions facilitating the interspecies exchange of microbes involved the close proximity of various species of caged domestic and wild animals, including bats; the mixing of their feces and blood after butchering; and the contamination of produce and throngs of shoppers. In this setting, “patient zero” was likely a daily customer who contracted the novel coronavirus and transmitted it to close contacts. Community spread was rapid because humanity lacks herd immunity against so newly emergent a pathogen—that is, we lack the protection that occurs when large enough numbers of the population are immune, through vaccination or prior exposure, thereby breaking the chain of transmission.
Of all the issues raised by COVID-19, the most important is preparedness. Joshua Lederberg, the microbiologist and Nobel Laureate, famously argued that, in the contest between humans and microbes, the only defense humans possess is their wits. One could add to Lederberg’s formulation our capacity to collaborate—if we so choose.
Unfortunately, when COVID-19 appeared, it found a world that was not mobilized to confront a challenge, even though that challenge had been long foreseen. Since World War II we have lived in an age of ever-increasing numbers of emerging diseases. In 2008, researchers identified 335 human diseases that had emerged between 1960 and 2004, most of them of animal origin. Their names now run the gamut from A to Z—from Avian flu to Zika, and scientists caution that far more potentially dangerous pathogens exist than have so far been discovered. Particularly since the outburst of H5N1 influenza in 1997, the public health community has consistently sounded the alarm that future outbreaks are inevitable—particularly of pulmonary viral diseases, to which our society is highly vulnerable.
The question was not whether but when. According to the virologist Brian Bird, “We live in an era now of chronic emergency.” In addition, virologists stress that there is every reason to expect a disastrous pandemic in the near future rivaling the 1918 outbreak known as the “Spanish influenza.” Synthesizing the scientific literature in 2012, David Quammen, in his book Spillover, forecast the “next human pandemic.”
In the years leading up to the current pandemic, we have faced challenges that could have been regarded as dress rehearsals urgently demanding our intelligence to organize and fund a coherent response. Between 2003 and 2016 these included outbreaks of avian flu, SARS (severe acute respiratory syndrome), MERS (Middle East respiratory syndrome), Marburg, and Ebola.
Unfortunately, along with outbreaks, a recurring pattern of societal amnesia has prevailed. Each microbial threat has been followed by a period of frenetic activity at every level, internationally and nationally, but has concluded with a lapse into forgetfulness. The interval between the SARS crisis of 2003 and the Ebola epidemic is illustrative. Immediately after the SARS experience, the World Health Organization (WHO) produced a Global Influenza Preparedness Plan (2005) to establish guidelines for country-by-country efforts; revised the International Health Regulations to include emerging disease threats as notifiable events; and devised its own rapid response capabilities. In the same year the US government issued a National Strategy for Pandemic Influenza and allocated funding for that purpose. Similar plans were drawn up by the Department of Defense, the Veterans Administration, the fifty states, and a series of major companies in the private sector.
But as the emergency receded and fear subsided, citizens and governments reverted to business as usual. Funds pledged to emergency response through the WHO—the agency charged with coordinating the international response to health emergencies—and the Centers for Disease Control (CDC) in the United States and its sister agencies abroad were slashed by administrations of both parties alike. In the same fashion, funds pledged through health departments, governments, and private laboratories, were also slashed. Agencies charged with coordinating the response at international, federal, and state levels were disbanded and their leaders removed.
Predictably, the same thing recurred after the Ebola emergency in West Africa. In 2018, on the very day that a new Ebola epidemic began in the Democratic Republic of the Congo, President Trump dismissed the chair of the National Health Security Council and dissolved the team. As the director-general of the WHO noted, the world has alternated between feast and famine concerning epidemic disease, content to imagine that periodic lurches into sudden improvisation and declarations of good intentions will carry the day. The WHO appointed a commission in 2018 to assess global preparedness for the next microbial challenge after the relaxation of efforts since SARS. The report, issued in 2019, considered the world and its individual countries to be comprehensively unprepared for the long-anticipated challenge. The poignant title of the report was A World at Risk.
When COVID-19 began its global spread, it met with success in part because the sentinels had stood down and the world slept. Here the stance taken by the United States is critical: it is the remaining superpower and economic giant; it provides the crucial funds for the efforts of the WHO; and the CDC is the agency that sets the gold standard for international response. Despite the repeated warnings since 1997, an important driver of present sufferings is the position of the American president, who continues to present the pandemic as an unforeseen tragedy.
A more fitting question is whether, after COVID-19 abates, the world will return to complacency or decide upon a sustainable, long-term assessment of the likely challenges and organize the means to meet them. Scientific research, enhanced healthcare infrastructures, close international collaboration, health education, protection of biodiversity, and ample funding will all need to be deployed around the globe if we are to secure our civilization. We can no longer afford to sleep.
Frank M. Snowden is Andrew Downey Orrick Professor Emeritus of History and History of Medicine at Yale University. He is the author of Epidemics and Society: From the Black Death to the Present, to be published in paperback, with a new preface, from which this is adapted, in May. His previous books include The Conquest of Malaria: Italy, 1900-1962 and Naples in the Time of Cholera, 1884-1911.