GUANGDONG (CHINA DAILY/ASIA NEWS NETWORK) - Only one in a sample of 1,099 patients infected with the new coronavirus was found to have an incubation period of as long as 24 days, a top Chinese scientist has clarified.

The time between initial exposure and development of the first symptoms of the illness is based on the patient's account of the illness.

Dr Zhong Nanshan, a prominent scientist who is leading a government-appointed panel of experts to help control the coronavirus outbreak, said on Tuesday (Feb 11) that caution is needed because there is not enough evidence to regard 24 days as the longest incubation period for the coronavirus, Xinhua reported.

The median incubation period is three days, less than the estimated 5.2 days, according to the research conducted by Dr Zhong and his team, while in rare cases, the incubation period can reach 24 days.

The findings were published on Sunday on medRxiv, the free online archive and distribution server for complete but unpublished medical papers.

The research is based on a sample of 1,099 coronavirus patients selected from 552 hospitals throughout China. The median age of the patients is 47.

Dr Zhong stressed that only one patient reported a 24-day incubation period.

More research and comments from other doctors is needed.

"The information in the paper should not be overinterpreted," Dr Zhong said.