GENEVA/BEIJING • The World Health Organisation (WHO) said it was raising its assessment of the global risk to "very high" from "high", which its head of emergencies, Dr Mike Ryan, said was intended to put the national authorities on full alert.

"I think this is a reality check for every government on the planet - wake up, get ready, this virus may be on its way and you need to be ready," Dr Ryan said on Friday.

But he also stressed it would be unhelpful to declare the disease a pandemic at this point when people are still trying to contain the coronavirus, adding that the existing data does not support the concept of a pandemic so far.

"A pandemic is a unique situation, in which all citizens on the planet will likely be exposed to a virus within a defined period of time," said Dr Ryan.

However, in the case of the coronavirus, it has been proven that the course of the epidemic can be significantly altered through containment measures and robust public health response, he said.

The latest WHO figures indicate that more than 85,000 people have been infected, with 2,835 deaths in China and dozens more in other parts of the world.

Mexico, Nigeria, Estonia, Denmark, the Netherlands and Lithuania reported their first cases on Thursday and Friday, all with travel history connected to Italy - the worst-affected European country.

Mexico is the second Latin American country to register the virus, after Brazil, and the Nigerian case is the first in sub-Saharan Africa.

A Chinese official said that some recovered patients had been found to be infectious, suggesting the epidemic may be even harder to eradicate than previously thought.

WHO spokesman Christian Lindmeier said that the organisation was looking very carefully into reports of some people getting re-infected.

REUTERS, XINHUA