The world has officially entered pandemic panic mode, with countries resorting to unprecedented measures to stop the spread of the new coronavirus. France has shut down the Louvre, Macau has closed its casinos, and the NBA is shutting down high-fiving fans. In my country, Australia, the government is attempting to shut down the toilet paper hoarding, which has reached ridiculous levels, with knives being pulled in Sydney supermarkets.

Other countries are going further by shutting down borders—something sovereign nations are allowed to do in response to public health threats under the International Health Regulations.

As news of the virus first began to spread, many countries put in place bans preventing those who had recently been in China from entering their borders. But the list of places that nations have sought to prevent people traveling from has expanded as the virus itself has spread. A constantly updating list on the International Air Transport Association website tracks the travel restrictions each country currently has in place, showing the state of disarray global transit is in. A growing number of countries won’t let you in if you’ve been in Italy, Iran, South Korea, Hong Kong, Singapore, or Japan in the past two weeks. The U.S. is currently banning foreigners who have been in China or Iran in the past 14 days (Trump having walked back suggestions that the coronavirus called for a Mexico border shutdown), but those within the U.S. are themselves personae non gratae in a number of other, unaffected countries, particularly in Pacific island nations, such as Samoa or the Solomon Islands. But there’s one country in the region taking this strategy further than any other: the Federated States of Micronesia.

Micronesia, made up of the island states of Pohnpei, Kosrae, Chuuk and Yap, has banned entry to anyone (airline crew excluded) who has been in any country with a confirmed case of coronavirus in the past fortnight—a list which is turning into more than half the globe. As of Wednesday afternoon, the list of afflicted countries sits at 84, and grows every day. No one who has been in China since January 2020 is allowed to enter Micronesia, quarantine or no. If you want to enter, you will likely first have to go to one of a shrinking number of unaffected countries, spend 14 days there, and hope it doesn’t join this list. Micronesia has also banned its own citizens from traveling to affected countries, essentially sequestering itself from the rest of the world. Donald Trump, eat your heart out.

This all-out ban may seem intense, but it is in many ways extremely reasonable. Aside from New Zealand, which has two confirmed cases, Pacific island nations have yet to register any cases of the coronavirus. That’s a relief, because Pacific island nations are particularly vulnerable to viruses like this, in terms of both their health care and immune systems.

The World Health Organization’s Western Pacific branch has a cooperation strategy specifically for Pacific island countries, which very quickly produced a Novel Coronavirus Preparedness and Action Report, followed by a six-month Pacific Action Plan. In a February blog post, regional director Takeshi Kasai warned Pacific island countries that it was time to “intensify preparedness.” Of course, not all of the Pacific countries are taking things as far as Micronesia. But they all go further than most of the rest of the world. The Solomon Islands, the Cook Islands, Samoa, and Kiribati have long lists of places entrants can’t have been to recently, and unlike many countries, they offer no exceptions for their own citizens. Samoa’s own minister of commerce, industry, and labor became one of the first Samoans to be refused entry at the airport and was deported to Fiji earlier this week. Kiribati has continued a hold on all Chinese visa applications. The Cook Islands has canceled 11 incoming cruise ships, costing it precious tourism dollars, with Prime Minister Henry Puna telling reporters, “It’s everything to do with what is best for this little paradise.”

The Pacific islands face a number of geographic and population-specific outbreak challenges. Having multiple small islands with vast distances between them can make infectious diseases easy to spread but hard to treat. The coronavirus would likely spread quickly through a small, concentrated island population, especially within communities where up to 20 people can live in one house, as happened with a recent deadly measles outbreak in Samoa. The dispersed nature of these islands, meanwhile, could make communicating public health warnings all the more difficult.

These nations’ health care systems are also less equipped to deal with an epidemic, with limited resources and facilities. As Kasai wrote: “There are two mains risks of importance to the Pacific. First, health care facilities could rapidly become overwhelmed, with even a relatively small number of COVID-19 cases. … Another major risk is that people with even mild symptoms may come to the health facilities, potentially amplifying the virus’ spread by infecting other patients.” Devex reports that the health workforce may also be underprepared for such an outbreak, with a lack of training and retention. Australia and New Zealand are supplying a range of assistance throughout the region, including providing individual countries with supplies to treat 50 to 100 cases and testing suspected samples in Australian labs (all of which have been negative). But if there is an outbreak, foreign emergency medical teams will likely be required.

The good news is that many Pacific countries have spent the past few years strengthening their outbreak preparedness, implementing strengthened surveillance systems as well as early-warning and response systems—which may be part of why the virus has yet to reach their shores.

If the virus is to infiltrate the Pacific islands, residents may face heightened mortality risks due to their lower levels of immunity to outside diseases, their natural isolation forming a double-edged sword. As an article in Frontiers in Immunology explains, indigenous people in the Pacific (Melanesians, Polynesians, Micronesians, Papuans, and indigenous Australians) are overrepresented when it comes to infectious diseases. But it’s not just due to poverty, education, and access to health care; rather, this overrepresentation can be attributed to genetic and microbiotic factors, and historic isolation. When it came to the devastating 1918 flu, indigenous populations in America and the Pacific suffered far worse than many others, with a lack of previous exposure and “naïve” immune systems making the disease harder to survive. The Pacific had among the highest mortality rates, with Tonga, Tahiti, Nauru, and Western Samoa losing up to 20 percent of their populations in a matter of months. (Iran, similarly, was hit harder than most, likely for similar reasons to its disproportionate coronavirus caseload today.)

In a globalized world, it’s hard to imagine many communities that could shut themselves off like Micronesia has—other than North Korea, that is. (North Korea claims it has registered no cases of COVID-19, despite sitting between the two most infected countries. Kim Jong-un has just sent South Korea a “get well soon.”) But this type of self-quarantine is not unprecedented. As the Guardian explored this week, one Colorado town managed to dodge the 1918 flu via a “de facto lockdown.” Gunnison, a farming and mining town with a population of about 1,300, enacted a “quarantine against all the world,” erecting barricades, closing schools and churches, banning public gatherings, and arresting violators, for four months—and it worked. This time around, Pacific islands are the ones with a “quarantine against all the world,” and they are doing everything they can to prevent COVID-19 getting in.

The Pacific islands have sometimes been considered an attractive place to be during a pandemic. In World War Z, a book that feels increasingly relevant, the isolated and zombie-free Pacific region was on the receiving end of a refugee influx. If the world really does become flooded with COVID-19, the politically and physically isolated Pacific island nations may indeed become an attractive destination for those looking to escape it. But until we start respecting their wishes on the epidemic expected to one day drive them from their homes, they certainly have no good reason to let us into theirs.

Future Tense is a partnership of Slate, New America, and Arizona State University that examines emerging technologies, public policy, and society.