The World Health Organization said on Monday that it remained unclear if the deadly virus is contagious during its incubation period before symptoms appear. It did not immediately confirm assertions made by Chinese authorities that people who are infected can spread the disease before they show any symptoms of fever or respiratory difficulties.
The virus is believed to have originated late last year in a Wuhan market illegally selling wildlife. Much is not known, including how easily it spreads and just how deadly it is.
The World Health Organization, which has sometimes been criticised for its handling of past disease outbreaks, admitted an error on Monday (Jan 27) in its risk assessment of China's deadly virus.
The Geneva-based UN agency said in a situation report late on Sunday that the risk was very high in China, high at the regional level and high at the global level.
In a footnote, the WHO explained that it had stated incorrectly in its previous reports on Thursday, Friday and Saturday that the global risk was moderate.
The correction of the global risk assessment does not mean that an international health emergency has been declared.
The WHO on Thursday stopped short of declaring the novel coronavirus a public health emergency of international concern - a rare designation used only for the worst outbreaks that would trigger more concerted global action.
The virus, which was first identified in the city of Wuhan in China on Dec 31, has since infected more than 5,000 people worldwide, including a few cases identified in over a dozen other countries. More than 100 people have died - all of them in China.
WHO chief Tedros Adhanom Ghebreyesus, who is visiting China this week to discuss ways of containing the outbreak, came under intense questioning from reporters on Thursday over his decision not to declare the emergency.
At the briefing at WHO headquarters, however, Tedros had said that the designation could be changed at any moment and that the global risk from the outbreak was high.
This is an emergency in China but it has not yet become a global health emergency. It may yet become one, he said.
WHO's risk assessment is that the outbreak is a very high risk in China, and a high risk regionally and globally.
WHO said the categorization was a global evaluation of risk, covering severity, spread and capacity to cope.
The agency added that the mistake made in three of its situation reports had been an error in the wording.