A World Health Organization medic prepares a vaccination dose for a front-line aid worker earlier this year in the small town of Mangina, Democratic Republic of Congo. Four Ebola response workers were killed and six others injured in two attacks overnight — one in Mangina and the other in Biakato Mines.

A World Health Organization medic prepares a vaccination dose for a front-line aid worker earlier this year in the small town of Mangina, Democratic Republic of Congo. Four Ebola response workers were killed and six others injured in two attacks overnight — one in Mangina and the other in Biakato Mines.