The news seemed to be positive: The number of new coronavirus cases reported in China over the past week suggested that the outbreak might be slowing — that containment efforts were working. Stocks ticked upward in the United States, as some analysts declared it safe again to invest in companies that depend on China.

But on Thursday, officials added more than 14,840 new cases to the tally of the infected in Hubei Province alone, bringing the total number to 48,206 — the largest one-day increase so far recorded. The death toll in the province rose to 1,310, including 242 new deaths.

The sharp rise in reported cases illustrates how hard it still is to grasp the extent and severity of the coronavirus outbreak in China, particularly inside the epicenter, where thousands of sick people remain untested for the illness…

Instead, officials in Hubei now seem to be including infections diagnosed by using lung scans of symptomatic patients. This shortcut will help get more patients into needed care, provincial officials said. Adding them to the count could make it easier for the authorities to decide how to allocate resources and assess treatment options.