Deadly Marburg Virus Outbreak in Rwanda: Scientists Race to Develop Vaccines

Rwanda is struggling with a dangerous outbreak of the Marburg virus, a highly contagious and deadly disease closely related to Ebola.

As of 1st October 2024, the virus has led to 10 deaths, with 29 confirmed cases, primarily among healthcare workers in the capital city, Kigali.

The Marburg virus outbreak in Rwanda is escalating, and global health officials are racing against time to test experimental vaccines and treatments to curb the spread of the virus.

What Is the Marburg Virus?

The Marburg virus is a rare, but severe hemorrhagic fever virus that belongs to the same family as the Ebola virus, the Filoviridae.

It was first identified in 1967 during outbreaks in Marburg and Frankfurt, Germany, and Belgrade, Serbia when laboratory workers were exposed to infected African green monkeys.

Marburg is a zoonotic virus, meaning it originates in animals—in this case, fruit bats, specifically Rousettus aegyptiacus.

These bats can transmit the virus to humans, and once infected, humans can spread the virus through close contact with bodily fluids, such as blood, vomit, and other secretions, or by coming into contact with contaminated surfaces like bed linens, medical equipment, or needles.

Unlike airborne viruses, Marburg is not spread through casual contact or by respiratory droplets, making it less likely to spread via air.

However, its high fatality rate—ranging from 24% to 88% depending on the strain and quality of care—makes it particularly alarming.

The virus can be contracted through unprotected handling of infected bats or through prolonged exposure to infected individuals, particularly in healthcare settings where patients are treated.

Symptoms of Marburg Virus

The Marburg virus has a wide incubation period, taking anywhere from two days to three weeks after exposure for symptoms to appear.

Initial signs of infection include sudden onset fever, chills, headache, and muscle pain. In some cases, a distinct, non-itchy rash may develop.

As the disease progresses, more severe symptoms manifest, including nausea, vomiting, chest pain, and abdominal cramps. In its most severe form, the virus causes hemorrhagic fever, leading to bleeding from the nose, gums, and other orifices.

Internal bleeding can cause blood to appear in vomit, urine, and stools, leading to organ failure, shock, and death.

People infected with Marburg may also exhibit severe psychological effects such as confusion, irritability, or delirium due to the damage the virus causes to the central nervous system.

Unexplained bleeding or bruising is often the most recognizable sign of the virus and occurs during the later stages of the disease.

The ability to spread the virus is highest during this late phase, making contact tracing and early identification of cases crucial for containment.

Marburg Virus Outbreak in Rwanda

The Marburg virus outbreak in Rwanda began in late September 2024, marking the first instance of the disease in the country.

Most cases have been concentrated in Kigali, and the virus has already spread to seven of Rwanda’s 30 districts. Of the 29 confirmed cases, 18 patients remain in treatment, and health officials fear the numbers could rise if the virus is not quickly contained.

The situation has been exacerbated by the fact that many of those infected are healthcare workers who were unknowingly exposed to the virus while treating patients.

According to the Rwandan Ministry of Health, over 100 people who have been in contact with confirmed cases are being closely monitored or placed in isolation.

The government has identified several hotspots where efforts are being focused to prevent further transmission, and local authorities are urging the public to remain calm and continue with their daily activities, assuring citizens that every effort is being made to contain the outbreak.

However, containing the virus is not an easy task. Unlike some other African countries that have experienced multiple outbreaks of the Marburg virus or Ebola, Rwanda has never dealt with an outbreak of this nature.

Nonetheless, Rwanda is better equipped than many other sub-Saharan African nations in terms of public health infrastructure.

International organizations such as the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) are working closely with Rwandan health authorities to provide testing kits, medical supplies, and expert support for contact tracing and quarantine efforts.

Vaccines and Treatments in Development

Despite the rising death toll, there is hope that experimental vaccines and treatments may help halt the Marburg virus outbreak in Rwanda.

While no approved vaccines or treatments currently exist for the Marburg virus, several candidates are being fast-tracked for testing.

One of the most promising is a vaccine developed by the Sabin Vaccine Institute in Washington, D.C.

This vaccine uses a modified chimpanzee adenovirus to instruct human cells to produce a protein that triggers an immune response against the Marburg virus.

Early trials in the United States involving 40 healthy participants showed that the vaccine is safe and generates a strong immune response in most people.

The vaccine is currently undergoing larger trials in Uganda and Kenya, and Sabin is working with the Rwandan government to determine how many doses can be made available.

The World Health Organization has named the Sabin vaccine as the top candidate for testing during an outbreak, and if the outbreak in Rwanda continues to expand, health officials hope to begin using it under a ring vaccination strategy.

Ring Vaccination Strategy

The ring vaccination method was used successfully during the 2014–2016 West African Ebola outbreak.

This strategy involves vaccinating all individuals who have been in close contact with an infected person, as well as the contacts of those contacts.

By forming a “ring” around the virus, health officials aim to stop the spread by protecting those most likely to be exposed.

If implemented in Rwanda, this approach could prevent future transmission, but it requires swift action and sufficient vaccine doses, both of which are currently uncertain.

Other vaccines are also in development. A team at the University of Oxford is working on a similar vaccine that has shown promise in early-stage trials in the United Kingdom.

Meanwhile, the International AIDS Vaccine Initiative (IAVI) is working on a Marburg vaccine based on the successful Ebola vaccine model, but production of this vaccine has only just begun, and no doses are yet available.

Experimental Treatments

In addition to vaccines, scientists are looking to test experimental treatments. The WHO has already approved the potential use of remdesivir, an antiviral drug that was previously tested during Ebola outbreaks and widely used during the COVID-19 pandemic.

Monoclonal antibody treatments, which have shown promise in animal studies, are also being considered. However, as with vaccines, these treatments are still in the experimental stage, and their effectiveness against the Marburg virus has yet to be proven in human trials.

The World Health Organization has called on the global community to support Rwanda’s efforts to contain the outbreak while stressing the importance of gathering data on the safety and efficacy of these experimental vaccines and treatments during this time.

Ira Longini, a biostatistician and member of the Marburg Virus Vaccine Consortium (MARVAC), believes that this outbreak offers an opportunity to gather crucial information that could lead to the approval of a Marburg virus vaccine.

International Response

Global health organizations have mobilized quickly in response to the Marburg virus outbreak in Rwanda.

In addition to the WHO and CDC, teams from the African Union, Médecins Sans Frontières (MSF), and other international relief organizations are on the ground, providing expertise and resources to help Rwanda’s health ministry manage the crisis.

The WHO has sent a team of seven global experts in hemorrhagic fevers to assist with public health responses, while the CDC has bolstered testing and contact tracing efforts in Kigali.