Story highlights

NEW: Nearly 800 in Guinea who'd been in contact with Ebola sufferers get experimental vaccine

NEW: A 30-year-old woman who died in a hospital in Monrovia, Liberia, had the virus, the WHO says

Liberia has twice before been declared Ebola-free -- in May 2015 and in September

CNN  — 

Two steps forward, one step back.

That’s the reality Friday in the fight against Ebola, with the World Health Organization announcing first that hundreds would get experimental vaccines in Guinea, then a short time later that the deadly disease has reemerged in Liberia.

All this comes days after the same international health body declared that the Ebola outbreak in West Africa was no longer a public health emergency of international concern.