The good news with this kind of endemicity is that it doesn’t have to be permanent. Reversing human endemicity is hard, yes—but it’s possible. “If it’s just spreading in humans it can be controlled—eventually—through vaccination and natural immunity,” Amesh Adalja, a public-health expert at the Johns Hopkins Center for Health Security, told The Daily Beast.

But monkeypox was originally a “zoonotic” animal virus. It circulates in rodent and monkey species in West and Central Africa, where outbreaks in the human population are frequent.

If the pox finds a home in some animal species in North America or Europe—say, squirrels, rats or prairie dogs—it’ll be all but impossible to eradicate regionally. “Game over,” Lawler said. The pox will be all around us, probably forever, just waiting for opportunities to spread from animals to people. Outbreaks will be frequent and big, just like they are now in West and Central Africa.

To be clear, the pox is not endemic in people or animals in the United States or Europe—yet. But the trends aren’t encouraging. “I do share the other scientists’ concern of containment and the virus becoming endemic in our U.S. rodent population,” Stephanie James, the head of a viral testing lab at Regis University in Colorado, told The Daily Beast.