Spread of China virus outside PRC a ‘concern’

BEIJING — World health officials expressed “great concern” Wednesday that a dangerous new virus is starting to spread between people outside China, a troubling development as China and the world frantically work to contain the outbreak. For a second day, the number of infections grew dramatically.

The new virus has now infected more people in China than were sickened there during the 2002-03 SARS outbreak. Early Thursday, the number of cases was 7,711, surpassing the 5,327 people diagnosed with SARS.

The death toll, which stood at 170 Thursday, is still less than half the number who died in China from SARS. Scientists say there are many questions about the new virus, including how easily it spreads and how severe it is.

In a report published Wednesday, Chinese researchers suggested that person-to-person spread among close contacts occurred as early as midDecember. Based on the first 425 confirmed cases, the researchers estimate that each infection led to 2.2 others on average. That’s a bit more than ordinary flu, but far less than such other respiratory diseases as whooping cough and tuberculosis. The rate for SARS, a cousin to this new virus, was estimated to be 3.

“Considerable efforts” will be needed to control the spread if this ratio holds up elsewhere, researchers wrote in the report, published in the New England Journal of Medicine.

Researchers report that the average incubation period was five days.