It has also been declared as ten times deadlier than Swine flu, as worldwide cases nearly reach 2 million.
Tedros Adhanom Ghebreyesus, WHO chief, in a virtual briefing from Geneva said the organisation was constantly learning about the bug sweeping the globe.
He said: “We can only say what we know, and we can only act on what we know.
“Evidence from several countries is giving us a clearer picture about this virus, how it behaves, how to stop it and how to treat it.
”We know that Covid-19 spreads fast, and we know that it is deadly, ten times deadlier than the 2009 flu pandemic.”
Coronavirus has so far killed 6.4 percent of people who have tested positive for it, including 12 percent of those in Britain.
Swine flu killed 1.1 percent of those it infected globally, according to WHO figures.
The WHO said 18,500 people died of swine flu, which was first found in Mexico and the US in March 2009,
The Lancet disputed that total and said it was between 151,700 and 575,400 deaths.
Their review included estimated deaths in Africa and Southeast Asia that were not accounted for by the WHO.
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Regardless of the efforts put in place, the WHO acknowledged “ultimately, the development and delivery of a safe and effective vaccine will be needed to fully interrupt transmission”.
A vaccine is thought to be at least 12 to 18 months away.
Scientists have been hard at work on 70 vaccines according to the WHO.
Closes to completion is one developed by Hong Kong-listed CanSino Biologics, which is phase two of testing.