OUTBREAK: Marburg Virus

Background

Marburg Virus Disease (MVD) is a zoonotic infectious disease caused by the Marburg virus (MARV) or Ravn virus (RAVV), belonging to the Filoviridae viral family. It was first discovered in 1967 after two simultaneous outbreaks occurred among laboratory workers in Germany and Serbia (formerly Yugoslavia). The laboratory workers were handling African Green Monkeys imported from Uganda. Since then, several MVD outbreaks have occurred predominantly in sub-Saharan Africa. Rousettus aegyptiactus bats are considered the natural animal reservoir for these viruses, and human infections have occurred after prolonged exposure to mines and caves where these bats live. 

MVD is a fatal disease with a case-fatality ratio of up to 88%. Clinical presentation is similar to Ebola virus disease. Infected individuals commonly develop fever, severe gastrointestinal symptoms, and haemorrhagic manifestations. MVD is transmitted via direct contact with an infected person’s (or animal’s) blood, bodily fluids, deceased body, or surfaces contaminated with these fluids, putting healthcare workers at increased risk. Among those who survive MVD, the virus is known to persist in the placenta, breast milk, and semen. There are no licensed vaccines or therapeutics against MVD however, several medical countermeasures are in development. 

MVD Outbreak in Tanzania (2025)

On 13 January 2025, the WHO informed its Member States of a suspected MVD outbreak in Tanzania. As of 11 January 2025, there are nine suspected cases and eight deaths from two districts in the Kagera region. Healthcare workers are among the suspected cases. If confirmed, this would be the second MVD outbreak in Tanzania. The first outbreak occurred in one district in the Kagera region between 21 March and 31 May 2023, resulting in nine cases and six deaths. Areas with animal reservoirs for MVD (the Rousettus aegyptiactus bat) are present in Tanzania.

The WHO has assessed the public health risk at a national level as high. They have also assessed the risk at a regional level as high due to cross-border movements between Kagera and surrounding countries. The global risk remains low. There are no licensed vaccines or therapeutics against MVD. However, several are in development and can be assessed during outbreaks. The ChAd3-vectored vaccine developed by the Sabin Vaccine Institute and the antiviral Remdesivir were used during the 2024 Rwanda MVD outbreak response. 

For more information about the 2025 Marburg Virus Disease outbreak in Tanzania, click here.

Key public health and research updates 

January 2025: 

• Tanzania and WHO confirm Marburg outbreak.
• The WHO informs its Member States of a suspected MVD outbreak in Tanzania.

December 2024:

• Rwanda declared the end of its MVD outbreak, which lasted approximately three months. During the outbreak, the WHO published the ‘Marburg virus disease: Strategic preparedness and response plan for Rwanda. October – December 2024’ outlining a response strategy to rapidly contain the outbreak, establish treatment centers, strengthen infection prevention and control, and engage with communities.

October 2024:

• The GloPID-R Research and Policy Team shared an updated ‘Marburg Outbreak Brief’.

August 2024: 

• The WHO published infection prevention and control research priorities in healthcare settings for Ebola and Marburg.

May 2023: 

• The Ministry of Health of Tanzania declared the end of its first MVD outbreak, which lasted approximately 2 months resulting in nine cases and six deaths.

April 2023: 

• The WHO Technical Advisory Group published candidate vaccines prioritized for inclusion in a Phase 1/2/3 study against MVD. 

March 2023: 

• The GloPID-R Research and Policy Team shared a ‘Marburg Outbreak Brief’ with its members which includes information from a rapid review of clinical trial registries. They found 12 active MARV research projects all of which were at the pre-clinical or basic science stage. 
• A WHO R&D meeting with the MARVAC consortium was held to discuss medical countermeasures in development and integrating research during an outbreak.

February 2023: 

• The WHO published a Marburg virus therapeutics and vaccine landscape outlining candidates in development.
• A systematic review by Rigby et al. (2023) on clinical management guidelines for high-priority viral haemorrhagic fevers found only two guidelines for MVD. Both were of limited scope and quality. 

July 2022: 

• A protocol for an international, randomized clinical trial platform based on a ring vaccination trial design, was developed by the Marburg Vaccine Trial Core Protocol Working Group.

June 2022: 

• The WHO R&D blueprint team published a Strategic Research Agenda for Filovirus Research and Monitoring (WHO-AFIRM) which outlines a long-term global strategy for filovirus research and monitoring between 2021-2031. 

Outbreak Specific Research Priorities

The WHO R&D team published a Roadmap outlining research priorities for Ebola/Marburg in 2019. A more updated Strategic Research Agenda for Filovirus (2021-2031) was published in 2021. This outlines strategic goals and milestones for Filovirus research under three pillars: Anticipation (to prevent and control outbreaks), Reinforcement (to develop and evaluate vaccines), and Cure (to develop post-exposure therapies). 

Relevant Links

• A WHO-Strategic Research Agenda for Filovirus. Research and Monitoring (WHO AFIRM). WHO-AFRIM Strategy Roadmap 2021-2031. 
• Ebola/Marburg Research and Development (R&D) Roadmap. January 2019 – Advanced draft.

Clinical Trials Landscape 

A review of the landscape of our funding data on clinical trials can be obtained by applying the filters: Disease =Marburg > Study type = Clinical > Research categories = Therapeutics research development and implementation AND/OR vaccines research development and implementation on the left-hand filter bar.   

We have collated additional data from clinical trials registries.  See our most up-to-date analyses here.  

Pandemic PACT Data

See below our data visualisations for Marburg virus disease research funding, including alignment to the outbreak-specific research priorities. Visit our ‘explore’ page and filter for Marburg to review the details of the research grants funded and their linked publications.