Published on 03/02/2025
World Health Organization (WHO) and partners have immediately boosted their support to the Ugandan government’s response to an outbreak of Sudan virus disease outbreak (SVD, part of the Ebola family), including by facilitating access to a candidate vaccine and candidate treatments.
The first 2160 doses of the vaccine candidate and the treatments are already in Kampala, Uganda, as they were prepositioned as part of outbreak preparedness.
The vaccine trial processes underway include orientation of the research teams on the trial procedures, and logistics arrangements. Research teams have been deployed to the field to work along with the surveillance teams as approvals are awaited.
The candidate vaccine and the candidate treatments (a monoclonal antibody and an antiviral) are being made available through clinical trial protocols, which will make it possible to further document their efficacy and safety.
Uganda has experienced five previous SVD outbreaks. The last one was declared in September 2022 and ended in January 2023, with 164 cases and 77 deaths. During that outbreak, a WHO committee of external experts evaluated candidate vaccines and provided recommendations on their suitability for evaluation in Uganda, as part of a clinical trial against the SVD virus.
WHO is working with the Ministry of Health of Uganda and its designated Ugandan Principal Investigators and their teams from Makerere University Lung Institute and the Ugandan Virus Research Institute, as well as worldwide filovirus and trial experts and regulators, to initiate the trials.
The trials were designed via a global collaborative effort coordinated by WHO, that included developers, academic institutions, regulatory authorities, other experts and researchers from Uganda and other countries at risk of filoviruses outbreaks.
The aim of the vaccine trial is to evaluate a potentially efficacious candidate vaccine, and if efficacious, to possibly contribute to ending the ongoing outbreak and protect populations at risk in the future.
Those eligible to join the trial are those at highest risk of SVD, i.e. close contacts of a person who has been confirmed to have had SVD or who has died from the disease. The study sites will therefore be the locations where contacts of the case or cases reside. Study teams will be mobile and able to rapidly move to these areas to do their work using the ring vaccination approach.
WHO is working with the Ministry of Health and with Makerere University Lung Institute and the Ugandan Virus Research Institute, who will lead the trials’ implementation.
The development of the protocols and research priorities has been done via the MARVAC Consortium and the Collaborative Open Research Consortium (CORC) for the Filoviridae Family, and numerous developers facilitated the availability of the candidate vaccine and treatments: IAVI provided their candidate Sudan vaccine, Gilead provided remdesivir, an antiviral.
Among those supporting the trials’ implementation are the Coalition for Epidemic Preparedness Innovations (CEPI), the Africa Centres for Disease Control and Prevention, Canada’s International Development Research Centre, the European Commission’s Health Emergency Preparedness and Response Authority (HERA) and WHO. This rapid action is the result of tireless efforts to build international cooperation on research, innovation and evaluation and deployment of countermeasures in the face of dangerous pathogens.
While outbreaks of SVD are controllable without vaccines, control can be achieved more quickly using safe and effective vaccines. In the meantime, a comprehensive outbreak response is underway in Uganda to rapidly halt transmission, identify contacts and carry out epidemiological investigations, while enhancing community awareness.
WHO has allocated US$ 1 million from its Contingency Fund for Emergencies to help accelerate outbreak control efforts.
Sudan virus disease is a severe, often fatal illness affecting humans and other primates that is due to Orthoebolavirus sudanense (Sudan virus), a viral species belonging to the same genus of the virus causing Ebola virus disease. Case fatality rates of Sudan virus disease have varied from 41% to 100% in past outbreaks. There are no approved treatments or vaccines for Sudan virus, but early initiation of supportive treatment has been shown to significantly reduce deaths from Sudan virus disease.
