🇺🇸▼
Public health workers in the Democratic Republic of Congo are working hard to stop a growing outbreak of a rare Ebola virus. At the same time, other countries are creating new rules to keep their own populations safe. As of May 27, 2026, Congo has reported more than 1,000 suspected and confirmed cases. The number of deaths in Congo is over 250, according to the U.S. Centers for Disease Control and Prevention. Neighboring Uganda has also reported seven cases and one death. Several Americans who were in the region have been exposed to the virus.
Countries like the U.S., Canada, and others have announced measures such as screening incoming travelers. They also plan to isolate people who have been exposed. These steps are scientifically proven ways to effectively address outbreaks. However, recent decisions by Uganda and the United States stand out. They are not supported by epidemiological evidence. They also reflect a surprisingly similar way of thinking about how to control an outbreak.
On May 27, Uganda closed its border with Congo. Only a narrow set of exceptions apply, mostly for emergency aid workers. Those who cross the border will be subject to health screening and supervised isolation. The following day, the United States announced plans to send exposed Americans from affected countries to a quarantine facility in Kenya. Kenya is a country with no Ebola cases. However, as of May 29, a Kenyan court has blocked this move.
These are very different policies. Yet, both rely on a common assumption. This assumption is that creating geographic distance from a threat provides protection. However, surveillance, isolation, and response capacity are often more important. Both the Ugandan and U.S. moves have drawn criticism from public health and medical experts. They argue that managing outbreaks depends more on detection and monitoring than distance alone.
Both decisions emerge from a long-running debate in public health. The debate is about whether controlling where people are located is more effective than investing in the systems that identify, monitor, and treat disease. As an epidemiologist studying infectious disease outbreaks, I believe a look at the history of border restrictions and closures during epidemics helps explain why scientific consensus usually recommends against them.
The instinct to seal borders during outbreaks goes back centuries. Venice’s 14th-century “quarantino” was one of the earliest organized attempts by a state to regulate movement in the name of collective health. It worked because the unit of control was a ship. A ship is a discrete location that could be anchored offshore for a period of time.
A land border is a fundamentally different problem. As trade networks crossed continents, epidemic control encountered something maritime quarantine never had to solve. You cannot easily anchor people at a land border.
By the 19th century, repeated cholera outbreaks had made the problem international. European powers responded with waves of uncoordinated border closures and trade restrictions. These actions caused enormous economic damage without reliably stopping the spread of the disease.
In 1874, governments from around the world met in Vienna for the Fourth International Sanitary Conference. They aimed to address a problem that sounds remarkably modern. The goal was to control infectious diseases crossing borders without crippling trade and travel. Delegates explicitly rejected border closures and land quarantine. They called these methods “unworkable and consequently useless.”
The modern descendant of those 19th-century conferences is a set of global laws called the International Health Regulations. Their core purpose is straightforward. They make it safe for countries to report outbreaks honestly. They do this without fear that reporting will trigger economic punishment or travel bans.
The entire modern global health surveillance system rests on a single premise. Countries need to report outbreaks quickly. They must do so without fear of automatic economic punishment for reporting. If declaring an outbreak triggers immediate border closures and travel bans, governments have a powerful incentive to delay reporting.
This concern is not hypothetical. During the first SARS outbreak in 2003, China’s delays in official reporting contributed directly to the global spread of the disease. This delay was driven in part by concern about economic fallout. It prompted the World Health Organization to publicly accuse a member state of placing the world at risk. The International Health Regulations were most recently revised in 2005. This revision happened in direct response to that failure.
When the WHO declared the current Ebola outbreak a public health emergency of international concern on May 17, it explicitly warned against border closures and travel restrictions. The organization said these moves “have no basis in science.” This is because such actions push movement to informal border crossings that are not monitored. These actions can also compromise local economies. They negatively affect response operations from a security and logistics perspective.
For example, a mother trying to get a sick child to a clinic just across the border may not stop. This is because the formal crossing is shut. The Uganda-Congo border is several hundred miles long. It is crossed by numerous footpaths beyond formal border posts. Many people use these paths daily to visit family or to trade.
The public health system loses the ability to test, isolate, or trace those interactions. This matters especially for Ebola. The virus transmits only after symptoms begin. This means a person who can actually spread the virus is already identifiable through symptom screening. Therefore, case detection and isolation are far more effective than geographic restriction.
The U.S. decision to send exposed Americans to a quarantine facility in Kenya reflects a related instinct. The instinct is to keep the virus off native soil. But exposure has already occurred. So, the public health question is no longer how to prevent entry. It is how to monitor potentially exposed people safely and effectively. The plan is particularly controversial because it would transfer potentially exposed individuals to a country with no Ebola cases of its own. This is done despite the U.S. already possessing specialized facilities designed for exactly this purpose.
The Infectious Diseases Society of America criticized the plan. They noted that the United States has already invested heavily in specialized Ebola treatment centers. These centers are specifically designed to care for patients with highly dangerous infectious diseases. They warned that building and staffing a new unit in Kenya during an active outbreak raises questions about resources, timing, and quality of care.
Some countries did use border closures effectively during COVID-19. New Zealand, Australia, and Taiwan sharply restricted international travel. They paired these measures with intensive testing, quarantine, and contact tracing. But specific circumstances made those cases work. These included restrictions before the virus began spreading widely in the community. They also included island geography that naturally limited informal crossings. Finally, they involved aggressive internal measures running in parallel.
Remove any of those elements, and the effectiveness drops sharply. In these examples, the act of closing the border did not work alone. It bought time for setting up the infrastructure for testing and contact tracing.
These circumstances do not apply to Uganda’s border closing. Researchers estimate the virus had been transmitting for approximately six weeks. Uganda already has seven confirmed cases. A closure here is not a moat.
Governments face real pressure to act visibly during outbreaks. Border restrictions are easier to communicate to a worried public. This is compared to investments in surveillance infrastructure. Those incentives are understandable.
But history suggests that outbreaks are controlled less by where people are located. They are controlled by whether governments can identify cases quickly. They must trace contacts, isolate infections, and maintain public trust. In other words, borders alone do not stop outbreaks. The real work happens inside them.