In the heart of Rwanda, an alarming health crisis unfolds as scientists scramble to counter a lethal outbreak of the Marburg virus. As of September 30th, the central African nation has recorded 27 cases, with nine fatalities attributed to this highly virulent cousin of the Ebola virus, notorious for inducing haemorrhagic fever. Most cases have been concentrated among healthcare workers in Kigali, the capital, who are now at the frontline of this growing epidemic.
Despite the gravity of the situation, no officially approved treatments or vaccines exist for the Marburg virus. However, the unrelenting progression of the outbreak may present a rare opportunity for health experts to gather essential data on the efficacy and safety of potential vaccines and treatments. Historically, Marburg outbreaks tend to be small and swiftly contained, but should this current surge persist, researchers and public health officials are poised to take decisive action.
On September 30th, the World Health Organization (WHO) convened a pivotal teleconference, bringing together leading Rwandan scientists appointed by the government, alongside members of the Marburg Virus Vaccine Consortium (MARVAC). The consortium, comprising pharmaceutical companies, non-profit organizations, and researchers, is at the forefront of efforts to test potential treatments and vaccines, according to a WHO spokesperson.
Revival of Vaccination Strategy
The current outbreak in Rwanda has reignited plans for trials that were originally devised following a 2023 Marburg virus outbreak in Equatorial Guinea. That outbreak claimed 12 lives out of 17 confirmed cases, with an additional 23 fatalities deemed probable. However, despite the urgency, no experimental treatments were tested at the time.
Now, with the threat of the virus looming larger, biostatistician Ira Longini, based at the University of Florida and a key MARVAC member, indicates that should Rwanda’s outbreak continue, the goal is to trial at least one vaccine using a methodology known as ring vaccination. This strategy, which proved instrumental during the 2014–2016 Ebola outbreak in West Africa, involves vaccinating the contacts of infected individuals, creating a protective ‘ring’ around each case.
A WHO ethics committee has already greenlit trials for the vaccine, as well as for treatments such as the antiviral remdesivir, previously tested against Ebola and COVID-19. Additionally, monoclonal antibody treatments, which have shown promise in animal studies, may also be deployed. The next critical step is securing approval for these trials from Rwandan health authorities.
Vaccines in Development
Several vaccines are in various stages of development, with the most advanced being a candidate developed by the Sabin Vaccine Institute in Washington, D.C. This vaccine uses a modified chimpanzee adenovirus to instruct cells to produce a Marburg virus protein, thereby stimulating an immune response. In a recent trial involving 40 healthy participants in the U.S., the vaccine was deemed safe and successfully triggered an immune reaction in the majority of subjects. A larger trial is now underway in Uganda and Kenya.
While a spokesperson for the Sabin Institute has confirmed their collaboration with Rwandan authorities, they did not specify the number of vaccine doses currently available. Nonetheless, the WHO’s advisory committee has named Sabin’s vaccine as the top contender for trials in the event of a Marburg outbreak.
Parallel to this, a similar vaccine under development at the University of Oxford has also been designated as a priority for testing. Dr. Teresa Lambe, a vaccinologist leading Oxford’s vaccine effort, reports that initial trials in the UK have demonstrated the vaccine’s safety in a limited group of participants.
In New York, the International Aids Vaccine Initiative (IAVI) is developing another promising vaccine, similar to an existing Ebola vaccine. However, Mark Feinberg, IAVI’s chief executive, cautions that doses are not yet available, though production is slated to begin shortly. Feinberg emphasizes the competence of Rwanda’s health authorities, expressing optimism that they will be able to contain the outbreak swiftly, though he also warns of the potential for the virus to spread to neighboring countries, with potentially dire consequences.
Trials Could Yield Key Data for Future Outbreaks
With plans for clinical trials already outlined and the necessary infrastructure in place, there is hope that vaccines and treatments for Marburg will soon be deployed in Rwanda. Nancy Sullivan, a viral immunologist at Boston University, stresses that while this outbreak could provide crucial data on the virus, it’s likely that multiple outbreaks will be necessary to fully assess the efficacy of vaccines and treatments.
Sullivan notes that the key is to act without hesitation. “You can’t be overly concerned about the outbreak’s duration; you have to keep moving forward. It’s only one part of the broader trial effort,” she asserts, pointing to the broader need for persistent, global efforts in tackling this deadly virus.