GENEVA, Switzerland (AFP)—WHO vaccine experts on Friday recommended a full-scale human trial of the only existing approved Ebola vaccine to see if it offers cross-protection against a deadly strain spreading in the DR Congo.

The Ervebo vaccine has proved safe and efficacious against the more common Zaire strain of Ebola virus, and World Health Organization experts said early data, notably from animal trials, showed it may also give some protection against the rare Bundibugyo strain exploding in the DRC.

The recommendation came as the number of confirmed cases in the Democratic Republic of Congo went past the 4,000 mark, now standing at 4,053, including 1,850 fatalities.