WHO and Partners Enable Access to Candidate Vaccine and Treatments for Sudan Ebola Virus Outbreak in Uganda
The World Health Organization (WHO) and its partners have ramped up support for Uganda’s response to the ongoing outbreak of Sudan virus disease (SVD), part of the Ebola virus family. This includes facilitating access to a candidate vaccine and treatments. As part of outbreak preparedness, the first 2,160 doses of the candidate vaccine and treatments have already arrived in Kampala, Uganda.
WHO announced on January 31, 2025, that vaccine trial procedures are underway, including orientation of research teams on trial processes and logistics arrangements. Research teams have been deployed to the field to collaborate with surveillance teams as regulatory approvals are awaited.
The candidate vaccine and treatments, including a monoclonal antibody and an antiviral, are available through clinical trial protocols to assess their efficacy and safety. As of January 30, one confirmed case and 45 contacts were under surveillance.
Uganda has faced five previous SVD outbreaks, with the last occurring between September 2022 and January 2023, resulting in 164 cases and 77 deaths. During that outbreak, a WHO committee of external experts evaluated candidate vaccines and recommended their suitability for trials in Uganda.
WHO is working closely with the Ugandan Ministry of Health, the Makerere University Lung Institute, and the Ugandan Virus Research Institute, along with global filovirus and trial experts, to initiate the trials. The vaccine trial aims to evaluate the candidate vaccine’s efficacy, potentially contributing to controlling the outbreak and protecting at-risk populations. The trial will use a ring vaccination approach, targeting close contacts of confirmed or deceased SVD cases.
The trials were designed through a global collaboration coordinated by WHO, involving developers, academic institutions, regulatory authorities, and experts from Uganda and other high-risk countries. The protocols and research priorities were developed through the MARVAC Consortium and the Collaborative Open Research Consortium (CORC) for the Filoviridae Family.
Several organizations have supported the implementation of these trials, including IAVI, which provided the candidate Sudan vaccine, and Gilead, which provided the antiviral remdesivir. Other supporters include the Coalition for Epidemic Preparedness Innovations (CEPI), Africa Centres for Disease Control and Prevention, Canada’s International Development Research Centre, and the European Commission’s Health Emergency Preparedness and Response Authority (HERA).
Although outbreaks of SVD can be controlled without vaccines, WHO emphasizes that control can be achieved more quickly with safe and effective vaccines. Meanwhile, a comprehensive outbreak response is underway in Uganda, focusing on halting transmission, identifying contacts, conducting epidemiological investigations, and increasing community awareness.
WHO has allocated $1 million from its Contingency Fund for Emergencies to accelerate outbreak control efforts.
Sudan virus disease is a severe, often fatal illness caused by Orthoebolavirus sudanense, a viral species in the same genus as the Ebola virus. Case fatality rates for Sudan virus disease have ranged from 41% to 100% in past outbreaks. While no approved treatments or vaccines exist for Sudan virus, early supportive care has been shown to reduce fatalities significantly.
