Yesterday afternoon, I called the UCLA epidemiologist Anne Rimoin to ask about the European outbreak of monkeypox—a rare but potentially severe viral illness with dozens of confirmed or suspected cases in the United Kingdom, Spain, and Portugal. “If we see those clusters, given the amount of travel between the United States and Europe, I wouldn’t be surprised to see cases here,” Rimoin, who studies the disease, told me. Ten minutes later, she stopped mid-sentence to say that a colleague had just texted her a press release: “Massachusetts Public Health Officials Confirm Case of Monkeypox.”
The virus behind monkeypox is a close relative of the one that caused smallpox but is less deadly and less transmissible, causing symptoms that include fever and a rash. Endemic to western and central Africa, it was first discovered in laboratory monkeys in 1958—hence the name—but the wild animals that harbor the virus are probably rodents. The virus occasionally spills over into humans, and such infections have become more common in recent decades. Rarely, monkeypox makes it to other continents, and when it does, outbreaks “are so small, they’re measured in single digits,” Thomas Inglesby, the director of the Johns Hopkins Center for Health Security, told me. The only significant American outbreak occurred in 2003, when a shipment of Ghanaian rodents spread the virus to prairie dogs in Illinois, which were sold as pets and infected up to 47 people, none fatally. Just last year, two travelers independently carried the virus to the U.S. from Nigeria but infected no one else.
The current outbreaks in Europe and the U.S. are different and very concerning. The first case, which was identified in the United Kingdom on May 7, fit the traditional pattern: The individual had recently traveled to Nigeria. But several others hadn’t recently been to endemic countries, and some had had no obvious contact with people known to be infected. This suggests that the monkeypox virus may be surreptitiously spreading from person to person, with some number of undetected cases. (The incubation period between infection and symptoms is long, ranging from 5 to 21 days.) “It’s uncommon to see this number of cases in four countries at the same time,” Inglesby said. (The count may soon be seven: Since we spoke yesterday, monkeypox has been confirmed in Sweden and Italy, while Canada is investigating suspected cases.)
These monkeypox outbreaks are also unique because … well … they’re occurring in the third year of a pandemic, “when the public is primed to be more acutely aware of outbreaks,” Boghuma Kabisen Titanji, a physician at Emory University, told me. “I don’t think that’s necessarily a good thing.” When it comes to epidemics, people tend to fight the last war. During the West African Ebola outbreak of 2014, American experts had to quell waves of undue paranoia, which likely contributed to the initial downplaying of the coronavirus. Now, because the U.S. catastrophically underestimated COVID, many Americans are panicking about monkeypox and reflexively distrusting any reassuring official statements. “I don’t think people should be freaking out at this stage,” Carl Bergstrom of the University of Washington told me, “but I don’t trust my own gut feelings anymore, because I’m so sick of all this shit that I tend to be optimistic.”
Monkeypox, then, is a test of the lessons that the world has (or hasn’t) learned from COVID. Can we better thread the needle between panic and laxity, or will we once again eschew uncertainty in a frantic quest for answers that later prove to be wrong?
To be clear, monkeypox isn’t COVID—they’re different diseases caused by different viruses with markedly different properties. COVID was completely unfamiliar when it first appeared, but monkeypox is a known quantity, and experts on the virus actually exist. One of them, Andrea McCollum of the CDC, told me that based on existing studies, monkeypox doesn’t spread easily, and not over long distances through the air. It transmits via contaminated surfaces or prolonged proximity with other people, which is why most outbreaks have been small, and why people have mostly transmitted the disease to either household members or health-care workers. “This isn’t a virus that, as far as we’re aware, would really take off in a population like COVID,” she said. “It really requires close contact for human-to-human transmission.”
Of course, we have heard that before. In early 2020, many experts claimed that COVID spread only via contaminated surfaces or close-splashing droplets—hence the six-feet rules and hygiene theater. Now it is widely accepted that the disease spreads through smaller and farther-reaching aerosol particles—hence the importance of ventilation and masks. But that doesn’t mean history is repeating with monkeypox. A 2012 study suggested that the virus can persist in aerosols for several days—but that was under artificial laboratory conditions, and persistence is just one small part of the infection process. The fact remains that past monkeypox outbreaks have been inconsistent with a virus that travels as easily as the coronavirus. “Monkeypox does not scream ‘airborne’ at me; COVID-19 did,” Linsey Marr, an aerosol expert at Virginia Tech, told me.
Then again, Marr is less certain about monkeypox than she was about COVID. And Titanji notes that our knowledge of monkeypox is based on just 1,500 or so recorded cases, as of 2018. “I’ve seen a lot of people writing as if everything we know about monkeypox is definitive and finalized, but the reality is that it is still a rare zoonotic infection,” she said. For that reason, “I’m in Team Cautious,” she said. “We can’t use what happened with previous monkeypox outbreaks to make sweeping statements. If we’ve learned anything from COVID, it’s to have humility.”
For decades, a few scientists have voiced concerns that the monkeypox virus could have become better at infecting people—ironically because we eradicated its relative, smallpox, in the late 1970s. The smallpox vaccine incidentally protected against monkeypox. And when new generations were born into a world without either smallpox or smallpox-vaccination campaigns, they grew up vulnerable to monkeypox. In the Democratic Republic of Congo, this dwindling immunity meant that monkeypox infections increased 20-fold in the three decades after smallpox vanished, as Rimoin showed in 2010. That gives the virus more chances to evolve into a more transmissible pathogen in humans. To date, its R0—the average number of people who catch the disease from one infected person—has been less than 1, which means that outbreaks naturally peter out. But it could eventually evolve above that threshold, and cause more protracted epidemics, as Bergstrom simulated in 2003. “We saw monkeypox as a ticking time bomb,” he told me.
This possibility casts a cloud of uncertainty over the current unusual outbreaks, which everyone I spoke with is concerned about. Are they the work of a new and more transmissible strain of monkeypox? Or are they simply the result of people traveling more after global COVID restrictions were lifted? Or could they be due to something else entirely? So far, the cases are more numerous than a normal monkeypox outbreak, but not so numerous as to suggest a radically different virus, Inglesby told me. But he also doesn’t have a clear explanation for the outbreak’s unusual patterns—nor does anyone else.
Answers should come quickly, though. Within days, scientists should have sequenced the viruses from the current outbreaks, which will show whether they harbor mutations that might have changed their properties. Within weeks, European epidemiologists should have a clearer idea of how the existing cases began, and whether there are connections between them. As for the U.S., “there are currently no additional suspected cases” beyond the individual in Massachusetts, McCollum told me. But given the numbers in Europe, she’s standing by for more.
The U.S. is, of course, in a better position with monkeypox than with COVID. Although the nation hadn’t planned for a coronavirus pandemic, it has spent decades thinking about how to handle smallpox bioterrorism. The two cases of monkeypox in 2021 provided handy test runs for those plans, which are now unfolding smoothly. For example, the case in Massachusetts was identified when the patient’s physician, having reviewed reports from the U.K., called the state’s public-health department on Tuesday. Within 12 hours, the department had collected and tested the patient’s samples. The next day, more samples arrived at the CDC, which confirmed monkeypox. “All of that worked really well,” McCollum said. “We’re a fairly well-oiled machine.”
Also, there’s already a vaccine. One smallpox vaccine is 85 percent effective at preventing monkeypox and has already been licensed for use against the virus. And as another bioterrorism precaution, stockpiles of three smallpox vaccines are large enough “to vaccinate basically everyone in the U.S.” Inglesby said. And though monkeypox patients usually get just supportive care, a possible treatment does exist and has also been stockpiled: Tecovirimat, or TPOXX, was developed to treat smallpox but would likely work for monkeypox too.
Monkeypox may also be less deadly than is frequently claimed. The oft-cited fatality rate of about 10 percent applies to a strain that infected people in the Congo Basin. The West African strain, which several of the current cases have been linked to, has a fatality rate closer to 1 percent—and that’s in poor, rural populations. “We haven’t seen fatalities in people who’ve had monkeypox in high-resource settings,” Rimoin said.
Still, as COVID has shown, even when a disease doesn’t kill you, it can hardly count as “mild.” Monkeypox might not take off in the way that COVID did, but for those who get it, it remains a “substantial illness,” McCollum said. “If individuals are sick, they’re often sick for two to four weeks. It’s urgent to identify people early, get them treatment, and identify contacts.” It helps that one common symptom is an obvious rash, which looks like an extreme version of chickenpox. But unlike chickenpox, the monkeypox rash is usually preceded by a fever, the lesions are initially more painful than itchy, and the lymph nodes are often inflamed. “The constructive thing to do is to make sure that the public is aware of what monkeypox looks like,” Titanji said.
For that reason, she added, it’s important to avoid stigmatizing infected people. Many of the current cases are in men who identify as gay, bisexual, or men who have sex with men—an unusual pattern not seen in previous monkeypox outbreaks. That has raised questions about a new route of transmission, but sex obviously involves prolonged close contact, which is how the virus normally spreads. As COVID showed, early narratives about a disease can rapidly and prematurely harden into accepted lore. And if those narratives turn into stigma, they could stop people from coming forward with symptoms.
Communication might prove to be one of monkeypox’s hardest challenges, as it has been with COVID. “We need leaders who are saying, ‘Here’s what we know; here’s what we don’t know; we’ll find out; and we’ll be back tomorrow,’” Inglesby said. But some leaders have lost credibility during the recent pandemic, while others are being drowned out by armchair experts who have amassed large followings. “All of a sudden, everyone’s an expert in monkeypox,” Titanji said.