Incubation period of novel coronavirus as long as 24 days: study

Beijing, Feb. 10 (CNA) A new study on the 2019 novel coronavirus (2019-nCoV), which analyzed about 1,000 confirmed patients in China, concludes that the incubation period of the virus can be as long as 24 days.

The study, conducted by prominent Chinese epidemiologist Zhong Nanshan (鍾南山), who works at the State Key Laboratory of Respiratory Disease in Guangzhou, China, and his research team, was published Monday on medRvix, though it has not yet been peer-reviewed.

The study analyzed the medical records of 1,099 cases of the novel coronavirus. Of the patients, only 13, or 1.2 percent, had direct contact with wildlife, whereas nearly one third had been to the Chinese city of Wuhan, the center of the epidemic, and 71.8 percent had been in contact with people from Wuhan.

A quarter of patients analyzed had at least one underlying medical disorder.

The incubation period, which is defined as the duration from a patient's contact with a transmission source to the onset of symptoms, ranged from 0 to 24 days, according to the study.

The median incubation period was 3 days, shorter than another recent study which reported a median of 5 days, the study noted.

Of the patients, only 43.8 percent had a fever on initial presentation, though close to 90 percent developed a fever following hospitalization, the study showed.

This absence of a fever in cases of 2019-nCoV is much more frequent than in patients who contracted Severe Acute Respiratory Syndrome (SARS), and the study cautioned medical workers against relying too heavily on that one symptom in detecting cases.

During hospital admission, the most common complication patients suffered from was pneumonia (79.1 percent), while 3.37 percent suffered from acute respiratory distress syndrome (ARDS), a type of respiratory failure characterized by rapid onset of widespread inflammation in the lungs.

In severe cases of the novel coronavirus, patients suffered from complications at "significantly higher rates" than non-severe cases, the study showed.

The study also found that four out of 62 patient stool specimens tested positive for the virus, which supports the findings of earlier research conducted in China and the U.S.

In another four patients, traces of the virus was found in their gastrointestinal (GI) tract, saliva or urine.

These findings suggest that formite transmission, when an object contaminated with a virus transfers it to a new host, "might have played a role in the rapid transmission of 2019-nCoV."

As such, hygiene measures should take into account the spread of the virus via GI secretions, the study said.