In March 2020, a couple of months after the Centers for Disease Control and Prevention reported the first confirmed case of COVID-19 in the United States, editors at the journal Nature Medicine appended a note to a coronavirus study it had published five years prior. “We are aware that this article is being used as the basis for unverified theories that the novel coronavirus causing COVID-19 was engineered,” the journal editors wrote. “There is no evidence that this is true; scientists believe that an animal is the most likely source of the coronavirus.”