As the Delta variant of the coronavirus spreads in southeastern China, doctors say they are finding that the symptoms are different and more dangerous than those they saw when the initial version of the virus started spreading in late 2019 in the central city of Wuhan reports The New York Times. 

Patients are becoming sicker and their conditions are worsening much more quickly, doctors told state-run television on Thursday and Friday. Four-fifths of symptomatic cases developed fevers, they said, although it was not clear how that compared with earlier cases. The virus concentrations that are detected in their bodies climb to levels higher than previously seen, and then decline only slowly, the doctors said.

Up to 12 percent of patients become severely or critically ill within three to four days of the onset of symptoms, said Guan Xiangdong, director of critical care medicine at Sun Yat-sen University in the city of Guangzhou, where the outbreak has been centered. In the past, the proportion had been 2 percent or 3 percent, although occasionally up to 10 percent, he said.