Research shows 3-day median incubation period for coronavirus, 24 days in rare cases

The median incubation period of three days is lower than the estimated 5.2 days, according to research conducted by prominent scientist Zhong Nanshan (above). PHOTO: AFP

BEIJING (CHINA DAILY/ASIA NEWS NETWORK) - The median incubation period of the coronavirus is three days, while in rare cases, the incubation period can reach 24 days, recent research has found.

The median incubation period of three days is lower than the estimated 5.2 days, according to research conducted by Dr Zhong Nanshan, a prominent scientist who is leading a government-appointed panel of experts helping to control the coronavirus outbreak.

The findings could be used to guide the quarantine practice of targeting the close contacts of coronavirus patients, according to the research, whose findings were published on Sunday (Feb 9) on medRxiv, the free online archive and distribution server for complete but unpublished medical papers.

Mr Guan Weijie, a member of the research team, told Red Star News on Monday that only in very rare cases has the coronavirus incubated for 24 days, and there is no need to prolong the isolation period for suspected patients. The study, published on Sunday (Feb 9) on medical research archive medRxiv, is a prepublication paper and has not been peer-reviewed and therefore should not be used to guide clinical practice, medRxiv said.

The research was based on a sample of 1,099 coronavirus patients selected from 552 hospitals across China, with a median age of 47.

Among them, 2.09 per cent are medical workers and 43.95 per cent were residents in Wuhan, central China's Hubei province - where the virus was first found in December.

More than a quarter of them have not been to Wuhan or met any returnees from the provincial capital. The findings are consistent with recent reports of infections from family gatherings and transmission from people without any symptoms.

Female patients account for 41.9 per cent of the sample, more than a quarter have at least one underlying conditions, and only 1.18 per cent had direct contact with wild animals, the research said.

Absence of fever in 2019-nCoV cases was more frequent than in Sars and Mers infections, the study found. Such patients may be missed if the surveillance case definition focused heavily on fever detection, the researchers said.

The research found that the pathogen's fatality rate was 0.88 per cent.

As of Tuesday, the virus has killed more than 1,000 people in China with a total of confirmed cases reaching more than 42,600.

With input from Caixin Global.

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