GENEVA (AP) — The World Health Organization has formally announced the end of the Ebola outbreak in Liberia, joining Sierra Leone and Guinea — the epicenters of the latest outbreak — as Ebola-free.

WHO director Rick Brennan, director emergency risk assessment and humanitarian response, said Thursday was "a good day, an important day" thanks to the announcement.

Brennan noted a "general acknowledgment" that WHO was slow to react at the start of the outbreak, which has left some 11,000 people dead.