Pandemics Close Borders—And Keep Them Closed

“THIS IS WHY WE NEED BORDERS!” President Donald Trump tweeted on Monday morning. He offered no additional context, but it’s safe to assume the “this” in his tweet was the spread of the coronavirus pandemic. In recent months, his administration has taken progressive action to strengthen borders and travel controls in response to the virus.

Trump isn’t alone: Leaders around the world have restricted nonessential travel to varying degrees, some sealing off their borders entirely, to help curb the spread of the coronavirus.

They’re following a playbook centuries old, dating back to at least the Black Death of the 14th century. In fact, countering disease was one of the main justifications for early border controls at a time when boundaries between countries were marked more by contested territories than firm divisions. (It would not be until the 1600s that an atlas with delineated borders between European countries was published.)

In the past, these measures might have worked. But the history of disease-driven border lockdowns has some sobering lessons. One is that border controls tended to long outlast whatever crisis they were supposed to prevent, at the expense of trade and free movement. And they’re also very much a relic of their times. More recent disease eradication efforts, and the broad path of the coronavirus itself, show that prolonged border controls are more an expression of xenophobic policy than an enduring solution to an infectious threat. Today, there’s far more to gain through international cooperation than by keeping borders locked down.

A closer look at how governments successfully sealed off their countries in the past to prevent disease is enough to show that the scale of international travel and porousness of borders today is incompatible with such fixes long term, and that similar impulses today will take us only further from real solutions.

During the Black Death, the city-states of Italy used expanded border controls as part of their efforts to keep the plague at bay. Florence imposed fines on visitors from plague-affected cities and issued passes to travelers deemed healthy enough to move freely. In 1348, Venice began preventing ships in the harbor from docking for 30 days to see whether those on board came down with the plague. Venetian colonies and others followed suit. By 1383, Marseilles, France, had extended the isolation period to 40 days, leading to the to the term “quarantine” (from the Italian for 40: “quaranta”). Italian states used systems of armed patrol ships, observation posts and horse patrols to enforce disease controls that lasted until the 1850s.

The enforcement of that quarantine period was one of the earliest forms of regulating ship travel and was used during plague outbreaks for centuries afterward. The infrastructure and regulation for those systems became permanent, such as the designation of particular ports of entry and patrols to make sure they were used. The last European outbreak of plague attacked Marseilles in 1720, the result of lax enforcement of a quarantine on a ship from plague-ridden Cyprus.

After it subsided in Europe, the Black Death continued to ravage the Ottoman Empire. In the 1730s, Austria’s Sanitary Court Commission recommended a series of inspection stations along the border with Ottoman lands. People and goods were both quarantined, although practices and periods varied—tobacco leaves spread out and aired for seven days were considered purified, for example. Many travelers were held in quarantine for as long as 48 days, and if they developed plague symptoms, they could be shot. Similarly, evading the quarantine system was punishable by death. The system lasted until 1871.

Border controls against plague appeared to have helped—if you hold infected fleas and people in isolation for long enough, the fleas die and the people either die or get better. Certainly, the Austrian Empire remained free of plague after the middle of the 18th century.

And, perhaps as a result, travel and trade restrictions became an increasingly popular tool against the threat of new infections. The United States quarantined ships to prevent the spread of yellow fever in the 1790s, a practice repeated during subsequent outbreaks into the 19th century, and France briefly closed the border with Spain to prevent the spread of the same disease. In the 19th century, a number of countries briefly imposed quarantines in an attempt to protect against cholera.

Those controls, short of total exclusion, proved an ineffective tool against both diseases, in part because yellow fever is mosquito-borne and in part because, by the mid-19th century, it was simply too difficult to implement a leak-proof system of inspection, control and quarantine at borders. But that did not stop continued adoption of border controls.

As we see today with a surge in anti-Asian discrimination, it is not just that disease is associated with international travel and migration; it is associated with foreigners. This, too, is nothing new: Jews were blamed for the Black Death and burned to death in pogroms. The Irish were blamed for bringing cholera to the United States and the Italians for spreading polio. Tuberculosis was called “the Jewish disease.” Syphilis, first recorded in Europe infecting the armies of Charles VIII of France as he was fighting in Naples, was referred to as the Naples Disease, the Spanish sickness, the French Pox, the German Sickness and the Polish sickness as it spread—the name based on a combination of local prejudice and the course of infection. When it got to the Middle East, it was called “the European pestilence.”

Infection also became the justification for increasingly strict migration restrictions in countries, including in the United States. The Immigration Act of 1891, which provided a foundation for federal oversight of migration, banned criminals, polygamists, prostitutes, contract laborers, and those with a “loathsome or contagious disease.” It was increasingly used to selectively exclude ethnic groups considered undesirable. From 1898 to 1915, the proportion of immigrants denied access to the United States on medical grounds climbed from 2 percent to more than two-thirds. On the Mexican border, federal officials stripped migrants naked and showered them with kerosene. Some of America’s first undocumented immigrants were those who crossed unguarded sections of the Rio Grande rather than submit to the medical exam; up until that point, Mexican migrants hadn’t needed travel documents.

Infection as an excuse for nativism continues today. In 2014, Representative Phil Gingrey of Georgia wrote to the U.S. Centers for Disease Control and Prevention over disturbing “reports of illegal immigrants carrying deadly diseases such as swine flu, dengue fever, Ebola virus, and tuberculosis.” The reports would have been considerably more concerning had they been accurate. That same year, private citizen Donald Trump pushed for travel bans covering Africa to respond to the Ebola outbreak. And the past few weeks have seen Trump declare that wall-building would protect the United States from a disease far more prevalent here than in Mexico, while battling to rename COVID-19 the “Chinese virus.”

But the evidence continues to mount that, in a world of massive cross-border flows of people, border controls and travel bans simply aren’t an effective tool to keep infections at bay—not in the long term. Effective pandemic response takes the fight to the pandemic; it doesn’t wait for the pandemic to reach us. We know that from the most successful campaign against infection in history: the global fight against of smallpox. Led by the World Health Organization, that worldwide effort involved cooperation between Cold War rivals the United States and the Soviet Union to provide vaccines, equipment and technical advice to teams across the globe that monitored for outbreaks and responded with an immediate “ring vaccination” of contacts to limit the disease’s spread. The result: Smallpox was eradicated worldwide in 1980, and a disease that killed hundreds of millions of people in the past century has killed no one so far in the new millennium.

Certainly at this point in the COVID-19 outbreak, few people should be going to an airport or getting on a plane at a time when we’re trying to limit social contact. But after the immediate crisis of this pandemic has abated, the United States should be leading an effort to strengthen global capacity to respond to outbreaks. And there is a long way to go: In 2013, out of 193 member countries, the WHO found only 80 met the International Health Regulations with regard to core capacities required for hazard alert and response to disease outbreaks that might become pandemic. The U.S. Commission on a Global Health Risk Framework for the Future estimates that $4.5 billion a year would buy strengthened national health systems, international coordination and funding for research and development, and financing for coordination that would address some of the most urgent weaknesses in global health security. That number pales in significance compared with the multitrillion dollar price tag already attached to the economic disruption triggered by COVID-19.

For all the Trump administration has begun to take the coronavirus pandemic with the seriousness it deserves, the response has been slow and parochial. By the time a global pandemic threatens again, America should be part of a coordinated worldwide response that reduces the risk of outbreak, tackles outbreaks that do occur where they emerge, and cooperates on global response from vaccine production to cure research. Because in the long run, borders—and certainly walls—simply don’t stop viruses.