WHO chief Tedros Adhanom Ghebreyesus has warned that "the threat of a pandemic has become very real".
But he told reporters that "even if we call it a pandemic, still we can contain it and control it".
"It would be the first pandemic in history that can be controlled," he said. "We are not at the mercy of the virus."
He said China appeared to be bringing the epidemic under control, but warned that "the disease has not run its course".
