New cases of the coronavirus rose sharply after Chinese authorities changed the criteria for diagnosing the illness, raising questions about how soon the outbreak will peak.
On Thursday, health officials in Hubei province, the epicenter of the infections, announced the largest one-day jump in cases14,840 on Wednesday, about nine times the number of new cases a day earlier. Epidemiologists, government officials and investors may now need to recalibrate their projections for the trajectory of a virus that remains little understood.