More than 200 vaccine doses have been arrived in Beni, in the east of Democratic Republic of Congo, it said.
The latest confirmed case has been genetically linked to a 2018-2020 outbreak in North Kivu and Ituri provinces, which claimed nearly 2,300 lives.
Six people were killed in another flare-up from that same outbreak last year.
A WHO spokesman told Reuters the shots were provided by the organization and that inoculations would start on Thursday.
Congo's dense tropical forests are a natural reservoir for the Ebola virus, which causes fever, body aches, and diarrhea, and can linger in the body of survivors only to resurface years later.
The vast central African country has recorded 14 outbreaks since 1976. The 2018-2020 outbreak in the east was Congo's largest and the second largest ever recorded, with nearly 3,500 total cases.
Congo's most recent outbreak was in northwest Equateur province. Itwas declared over in July after five deaths. (NS/VOA)