OUTBREAK: Marburg Virus

Background

Marburg Virus Disease (MVD) is a zoonotic infectious disease caused by the Marburg virus (MARV), 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 MARV and human infections have occurred after prolonged exposure to mines and caves where these bats live. 

MVD can be 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. MARV 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 MARV is known to persist in the placenta, breast milk, and semen. There are no licensed vaccines or therapeutics against MARV however, several medical countermeasures are in development. 

Current Outbreak

On 27 September 2024, Rwanda declared its first outbreak of MVD. Most new cases were reported at the beginning of the outbreak, and two weeks after the outbreak declaration, there was a sharp decline in new confirmed cases. As of 22 November 2024, there have been 66 confirmed cases and 15 deaths. The last case detected was on 28 October 2024. The source of the infection is believed to be zoonotic after the index case was exposed to likely infected bats in a cave. Healthcare workers from two major hospitals in Kigali are most affected and account for approximately 80% of the confirmed cases. Kigali, Rwanda’s capital city, has an international airport and a road network to East Africa, raising concerns of further spread. 

The World Health Organization (WHO) has assessed the risk of this outbreak at a national level as ‘very high’, at a regional level as ‘high’, and at a global level as ‘low’. Rwanda and neighboring countries, with support from the WHO, are taking rapid actions, including engaging communities, to contain this outbreak. As of 7 October 2024, Rwanda has been administering vaccines provided by the Sabin Vaccine Institute to frontline responders as part of a Phase 2 trial. In addition, over five thousand vials of antiviral Remdesivir, which has demonstrated efficacy in non-human primates, have been provided by Gilead Sciences, Inc. for compassionate use.  

For more information about the ongoing Marburg Virus Disease outbreak in Rwanda, click here. 

Key public health and research updates 

November 2024:

• As of 9 November 2024, Rwanda has begun its 42-day countdown to declare the end of the outbreak after the last MVD patient was discharged from the hospital on 8 November 2024. 

October 2024:

• 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 centres, strengthen infection prevention and control, and engage with communities.  
• Gilead Sciences, Inc., has provided 5,100 vials of Remdesivir, an antiviral that has demonstrated efficacy against MVD in NHP studies, to Rwanda for use under compassionate grounds. 
• Sabine Vaccine Institute provides 700 investigational vaccine doses as part of a Phase 2 trial in Rwanda. Their chAd3-based vaccine has been used in Phase 2 trials in Kenya and Uganda with no safety reports and is demonstrated by a Phase 1 study to elicit a rapid immune response. Plans are in place to provide additional vaccines.
• WHO published an appeal classifying this outbreak as Grade 3, the highest level requiring major WHO support, and estimated that 7.7 million USD is required between October and December 2024 to provide necessary support.

September 2024:

• Rwanda confirms cases of Marburg Virus Disease for the first time.

August 2024: 

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

April 2023: 

• The WHO Technical Advisory Group published candidate vaccines prioritised 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 (relating to an outbreak in Tanzania and Equatorial Guinea) 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.