Early in 2020, on the same day that a frightening new illness officially got the name COVID-19, a team of scientists from the United States and China released critical data showing how quickly the virus was spreading, and who was dying.
The study was cited in health warnings around the world and appeared to be a model of international collaboration in a moment of crisis.
Within days, though, the researchers quietly withdrew the paper, which was replaced online by a message telling scientists not to cite it. A few observers took note of the peculiar move, but the whole episode quickly faded amid the frenzy of the coronavirus pandemic.