Martha Phillips knows exactly how it feels to suddenly find oneself up close to — and unprotected from — a deadly virus.In 2014, Phillips, an emergency room nurse, was at the bedside of a suspected Ebola patient in Sierra Leone when the disposable plastic guard protecting her face came loose.“I turned my head quickly and my shield came off,” she recounted. “So I am in an Ebola treatment unit and my eyes are completely exposed.” She stayed calm and quickly left the room.Phillips, 35 at the time, had arrived in a rural corner of northwestern Sierra Leone just as Ebola cases were surging in West ...