Monkeypox cases are popping up in several countries. Health experts are cautiously concerned, but this isn’t like Covid-19.
On Wednesday, May 18, the CDC confirmed a case of monkeypox in a Massachusetts man who had recently traveled to Canada. It wasn’t the first time the US had seen a case of monkeypox, a virus related to smallpox that causes flu-like symptoms and a rash, and can sometimes be deadly. Occasionally, public health authorities identify single cases in people recently returned from West or Central Africa, where the disease is more common. What’s different — and concerning — about this Massachusetts case is that it’s occurring as clusters of monkeypox infections are popping up in other countries where the virus is also rare. Since early May, more than 250 cases have been detected in Europe and North America: 100 in Spain, 37 in Portugal, 56 in England, and 23 in Canada, as of May 23. US authorities are investigating four additional suspected cases, two in Utah and one each in New York and Florida. (These numbers are changing rapidly; a University of Oxford epidemiologist tweeted a link to a makeshift tracker where you can see the latest figures.)
With so many monkeypox cases concurrently popping up in different countries, public health officials’ immediate questions are whether the cases are related, and whether monkeypox is spreading in other communities undetected.
“The worldwide concern from public health authorities is trying to understand how these are related to each other and what the causes are,” said Agam Rao, an infectious disease specialist and poxvirus expert at the CDC. Only weeks into this outbreak, it’s too early to tell what exactly is going on, and whether this outbreak has epidemic potential. For the time being, said Rao, the general public doesn’t need to be particularly worried. “The risk is still very rare,” she said, and the strain of monkeypox currently being detected is relatively mild. Two years into a deeply divisive pandemic, word of another pathogen spreading unchecked might make some people want to launch themselves directly into the sun. But with monkeypox, the world faces a very different situation than in the early days of Covid-19. Monkeypox, unlike SARS-CoV-2, is a known quantity. We have more tools to prevent and treat it — far more than we did for Covid-19 at the outset of the pandemic — and both public health and the general public have had a lot of practice taking measures to prevent infections from spreading. Still, the trajectory of the outbreak is as yet uncertain, and public health experts remain vigilant. What is monkeypox? Monkeypox viruses generally circulate among wild animals in Central and West Africa, and usually spread to people when they eat or have other close contact with infected animals. The virus was first identified among research animals at the CDC in the 1950s (that’s how it got its name “monkeypox”), and for a long time afterward, human infections were sporadic, even in countries where lots of animals are infected. That’s partly because monkeypox is related to the smallpox virus, and immunity to smallpox is protective against monkeypox. But as of 1980, smallpox has been eradicated in humans, and vaccinations against smallpox have grown rare — and human cases of monkeypox have been on the rise. It’s still rare: According to the CDC, Nigeria has reported 450 cases since 2017, when public health authorities began seeing more cases among humans. Infection with the monkeypox virus usually causes a flu-like illness with fever, headache, muscle aches, swollen lymph nodes, and a rash.
