In the early days of the pandemic, scientists reported a reassuring trait in the new coronavirus: It appeared to be very stable. The virus was not mutating very rapidly, making it an easier target for treatments and vaccines.
At the time, the slow mutation rate struck one young scientist as odd. “That really made my ears perk up,” said Alina Chan, a postdoctoral fellow at the Broad Institute in Cambridge, Massachusetts. Chan wondered whether the new virus was somehow “pre-adapted” to thrive in humans, before the outbreak even started.