The mortality rate of the coronavirus may be much higher than previously thought, according to new research published in medical journal The Lancet.
There are confirmed coronavirus cases in 25 countries - with 305 people dying from the virus.
The study, released on January 30, looked at 99 people treated in isolation at Jinyintan Hospital between January 1 and January 20 after having been transferred from other hospitals across Wuhan, where the outbreak began.
Almost half of the group, comprising 32 women and 67 men aged from 21 to 82, had a history of exposure to the Huanan Seafood Wholesale Market, where 2019-nCov is believed to jumped from animals to humans, reports news.com.au.
Most, including a married couple, were vendors or market managers but two were shoppers who had visited the market only briefly.
By January 25, 32 of the patients had been discharged, 57 remained in hospital but 11 had died.
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That represents a mortality rate of 11 per cent — which is significantly higher than the early estimates of between two and three per cent by the World Health Organisation (WHO) and the Centers for Disease Control (CDC).
The report authors warned "additional deaths might occur in those still hospitalised".
SARS (severe acute respiratory syndrome) had a death rate of around 10 per cent and MERS (Middle East respiratory syndrome) 34 per cent.
Preliminary research indicated 2019-nCoV was more infectious than SARS and seasonal flu but less deadly and most experts are confident that continues to be the case.
US epidemiologist Dr Eric Feigl-Ding said the mortality rate findings were "much higher than expected" but said they should be viewed in context.
"To be clear, this mortality per cent is not the official 'Case Fatality Rate' (which is technically not a true rate since it doesn't have time), " he wrote on Twitter.
"This is just a selected example of infected patients seen in Wuhan hospital, not all infected patients. So let's cautiously interpret.
"The total per cent case fatality is likely lower because (a) lot of infected patients with less severe symptoms might not be in this hospital pool.
"At the same time, this is a small sample size. Also, it's encouraging that over 30 people were discharged (recovered?)"
Men at more risk than women
Another key finding of The Lancet research was that men appear to be more vulnerable to the disease than women.
While there were more male patients in the study pool than females, the authors said the ratio reflected the big picture — more men than women were contracting the virus, as was the case with SARS and MERS, which were also coronaviruses which made the animal to human jump.
"We observed a greater number of men than women in the 99 cases of 2019-nCoV infection," the authors wrote."
"MERS-CoV and SARS-CoV have also been found to infect more males than females.
"The reduced susceptibility of females to viral infections could be attributed to the protection from X chromosome and sex hormones, which play an important role in innate and adaptive immunity."
While about half the patients also had chronic underlying diseases, including heart problems and diabetes, the first two deaths, both men aged in their 60s, had no history of serious illness but were long term smokers.
The researchers concluded that the people most likely to contract the new coronavirus were older men with underlying health problems.
To date, more than 9500 people have been infected with the virus worldwide, including nine in Australia, and more than 213 people have died, all of them in China.