Uganda will begin vaccinating frontline health workers against Ebola next week as the threat increases of the deadly virus spreading from neighbouring Democratic Republic of Congo, the health minister said on Friday.An outbreak of Ebola in the DRC has claimed 180 lives so far, and with high numbers of people moving across the border "the public health risk of cross-border transmission of Ebola to Uganda was assessed to be very high", according to minister Jane Ruth Aceng."Compassionate use of the Ebola vaccine for healthcare and frontline workers," will begin on Monday, she told journalists.It will be the first time the vaccine is used in a country not in the midst of an active Ebola outbreak.The DRC's health ministry said on Thursday it had recorded 285 possible Ebola cases in the highly-restive northeastern region of North Kivu, which is home to a clutch of armed groups.It is the tenth outbreak of Ebola in the country, then called Zaire, where the disease was first detected in 1976.More than 25 000 people have received an experimental vaccine in the DRC since August. Yonas Tegegn Woldemariam, the World Health Organisation representative in Uganda said the vaccine - rVSV-ZEBOV - was close to 100% effective and carried few risks. Most vicious species "There have been no major risks recorded up to now, just a normal reaction to a vaccine," he said.The drug targets the Zaire virus species, the most "vicious of the Ebola types", Woldemariam said.Concerns that an undiagnosed Ebola patient may arrive at a health facility seeking treatment led to the decision to vaccinate healthcare workers at the highest risk of contracting the highly-infectious hemorrhagic fever, in 40 facilities near the border.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook. Authorities insist vaccination will be totally voluntary and that frontline workers - who may include hospital cleaners and other auxilliary staff - would need to give "informed consent"."Currently 2 100 doses of the rVSV vaccine are available," Aceng said, with plans in place to increase that to 3 000.Although the "investigational vaccine" has not yet been licensed it was used in previous Ebola outbreaks in Guinea, Sierra Leone and DRC at the recommendation of the WHO's group of experts.The drug was donated free of charge to the Ugandan government by its manufacturer, Merck.In the worst Ebola epidemic to date, the disease struck the West African states of Guinea, Liberia and Sierra Leone in 2013-15, killing more than 11 300 people.