Uganda has received 1,200 experimental vaccine doses designed to work against the Sudan strain of the Ebola virus that will be used in scientific trials.
The country has confirmed 142 cases of the Sudan strain, with 56 deaths, since it announced an outbreak of Ebola in September.
The vaccine will be administered to people who have been in contact with those who tested positive for the virus, in what is called ring vaccination.
Researchers hope to recruit at least 3,000 people, aged six years and above, to take part in the study, which will be conducted by a team of Ugandan scientists.