A comprehensive response to a September 2024 Marburg virus disease (MVD) outbreak in two Rwandan hospitals may not only have reduced mortality rates, but could also offer public health systems an effective playbook for managing the highly lethal condition, say experts.
Among 66 people with confirmed MVD during the 25 September to 8 November outbreak, 15 patients died, a case fatality rate of just 23%, reported Sabin Nsanzimana, MD, PhD, of the Rwanda Ministry of Health in Kigali, and colleagues in The New England Journal of Medicine.
Medpage Today reports that this compares with an 83% fatality rate in a Democratic Republic of Congo outbreak in 1998-2000, and a 90% fatality rate seen in a 2004-2005 Angolan outbreak.
“Unlike past MVD outbreaks, which have been marked by high case fatality and delayed detection in remote regions, this outbreak saw the rapid initiation of a multisectoral response, which is likely to have contributed to a lower case fatality,” they wrote.
“Although direct comparisons across outbreaks are limited by differences in surveillance, healthcare capacity, and diagnostic access, this experience underscores the potential effect of early case identification, aggressive supportive care, and access to investigational treatments in mitigating mortality from MVD,” they added.
MVD is a severe, often fatal, infection passed from fruit bats to people. Person-to-person transmission occurs through direct contact with bodily fluids from infected people. Symptoms include fever, gastrointestinal symptoms, coagulopathy, and failure of multiple organs. The World Health Organisation estimates that the average MVD case fatality rate is 50%.
Outbreaks typically spread from remote regions to more populated areas. The Rwanda outbreak was unusual in that it began in two urban hospitals, not in rural communities. Of the 66 confirmed cases, 51 were healthcare workers.
The outbreak began in a Kigali academic tertiary care hospital, where a cluster of patients in the intensive care unit (ICU) showed severe febrile illness. Clinicians notified Rwandan health authorities on 25 September.
An investigation found that the source was probably a woman who had died in the hospital’s ICU after transferring from a regional hospital, and whose husband worked in a rural mine inhabited by Egyptian fruit bats. He had developed a febrile illness but recovered.
The first confirmed MVD case was an ICU patient who had been in a bed next to the deceased woman. An outbreak then developed in a second hospital, where a doctor who had treated that first confirmed MVD patient later worked.
By 27 September, health authorities activated a national emergency response and set up a dedicated treatment centre. Screening, triage, and isolation protocols were shared with all Rwandan health facilities, and health officials deployed rapid response teams to help local health staff.
Contact tracing identified 1 497 people who may have been exposed, including relatives, hospital staff, and other patients. Overall, officials tested 6 340 people for MVD.
The median estimated incubation period was 10 days, and symptom onset occurred a median of two days before hospital admission.
The most common symptoms among patients with MVD included fever (95%), fatigue (88%), and gastrointestinal symptoms (82%): 42% of people had haemorrhagic symptoms, and 17% had neurological symptoms.
Among those with a Ct value less than 25 (indicating a high viral load), 48% died, while only 5% of those with a Ct value of 25 or greater died.
Patients were treated with supportive care and investigational therapies, including the antiviral agent remdesivir and the monoclonal antibody MBP091, which targets Marburg virus. Supportive care consisted of crystalloid fluid resuscitation, transfusions for haemorrhagic complications, and broad-spectrum antibiotics and antifungals for secondary infections.
Clinicians gave remdesivir to 52 patients, including all critically ill patients receiving organ support or supplemental oxygen. Another 150 healthcare workers received post-exposure prophylactic remdesivir. Among the 52 patients given remdesivir, three died, compared with 12 of the 14 patients who didn’t get the antiviral.
Among the 10 patients who received MBP091, two died, while 13 of the 56 patients who didn’t receive the monoclonal antibody died.
By the end of October, 1 710 high-risk contacts and frontline health workers had been vaccinated with the chimpanzee adenovirus 3-vectored Marburg virus vaccine (ChAd3-MARV). Healthcare workers, laboratory staff, and burial teams were given vaccination priority.
By the outbreak’s third week, cases began to decline, and the dedicated treatment centre discharged its last patient on 11 November. The outbreak officially ended on 20 December, when no new cases had been reported for more than two incubation periods.
Study details
Marburg Virus Disease in Rwanda, 2024 — Public Health and Clinical Responses
Sabin Nsanzimana, Eric Remera, Menelas Nkeshimana et al.
Published in The New England Journal of Medicine on 10 September 2025
Abstract
Background
On September 27, 2024, Rwanda reported an outbreak of Marburg virus disease (MVD), after a cluster of cases of viral haemorrhagic fever was detected at two urban hospitals.
Methods
We report key aspects of the epidemiology, clinical manifestations, and treatment of MVD during this outbreak, as well as the overall response to the outbreak. We performed a retrospective epidemiologic and clinical analysis of data compiled across all pillars of the outbreak response and a case-series analysis to characterise clinical features, disease progression, and outcomes among patients who received supportive care and investigational therapeutic agents.
Results
Among the 6340 patients with suspected MVD who underwent testing, 66 had laboratory-confirmed MVD, 51 (77%) of whom were health care workers. The median estimated incubation period was 10 days (interquartile range, 8 to 13), and symptom onset occurred a median of 2 days (interquartile range, 1 to 3) before hospital admission. The results of epidemiologic investigations were highly suggestive of a zoonotic origin of the outbreak: an index patient was identified who had been exposed to Egyptian fruit bats at a mining site. The case fatality rate in the outbreak was 23% (15 deaths among 66 patients). Remdesivir and the monoclonal antibody MBP091 were used under expanded access and clinical trial protocols. In addition, 1710 frontline workers and high-risk contacts received the chimpanzee adenovirus 3–vectored vaccine ChAd3-MARV under emergency use authorization in a phase 2 clinical trial.
Conclusions
Implementation of containment measures, advanced supportive care, and access to investigational countermeasures may have contributed to reduced mortality from MVD in this outbreak. Enhancing surveillance, improving infection prevention and control in health care settings, and ensuring timely deployment of medical countermeasures will be critical for mitigating the effects of future filovirus disease outbreaks.
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Rwandan Marburg research to give clues on virus immunity
Rwanda starts Marburg vaccine trial