The 2014-2016 Ebola outbreak in West Africa infected more than 28,000 people, took more than 11,000 lives and spurred funders and vaccine developers to urgent action. Years later, Ebola has returned and the world still lacks any treatments or licensed vaccines to protect against it or the closely related, but lesser known, Marburg virus.

We need an effective vaccine to protect more than 100 million people that are currently at risk of infection, as well as the global community to which an outbreak could spread. That’s why Sabin, in partnership with the Vaccine Research Center (VRC) at the National Institute of Allergy and Infectious Disease (NIAID), and powered by proprietary technology licensed from GSK, is addressing the enormous threat that Ebola and Marburg pose to the health of communities worldwide by advancing the development of several candidate vaccines against these diseases.

Research & Development Agreements and Awards 

Through licensing agreements, partnerships and new funding, Sabin is actively advancing the development of Ebola and Marburg vaccines. Under an agreement with GSK, Sabin has exclusively licensed the technology for three clinical-stage ChAd3-based vaccine candidates against Ebola Sudan and Marburg viruses that were developed collaboratively by the U.S. National Institutes of Health and Okairos, which was acquired by GSK in 2013. The candidate vaccines were further developed by GSK, including Phase II development for the Ebola Zaire vaccine. 


Vaccine Candidate

Stage of Development

Zaire ebolavirusChAd3-ZAIVPhase I, Phase II
Sudan ebolavirusChAd3-SUDVPhase I
Marburg virusChAd3-MARVPhase I

The vaccine candidates have demonstrated strong safety profiles and immunogenicity results across 13 clinical trials. In total, the vaccines have been administered to more than 5,000 adults and 600 children, the majority of which were tested using the ChAd3 Ebola Zaire vaccine. In addition to numerous Phase I trials, the Ebola Zaire vaccine has been tested in three Phase II trials in Africa: two were conducted by GSK and one was conducted by the Partnership for Research on Ebola Virus in Liberia (PREVAIL), a clinical research partnership between NIAID and the Liberian Ministry of Health. The Ebola Sudan vaccine has been evaluated in three Phase I trials in Africa and the United States as a bivalent formulation with Ebola Zaire and will be evaluated in an upcoming Phase I study as a monovalent formulation. A Phase I study of the Marburg vaccine is ongoing in the United States. To read more information about the studies, please refer to our table of clinical trials.

To further develop the ChAd3-based vaccines, Sabin is partnering with the VRC at NIAID through a Research Collaboration Agreement. The VRC is an established research center for Ebola and Marburg vaccines and has been an important collaborator on the ChAd3 Ebola vaccine platform for more than a decade.

In addition to the ChAd3 platform license, Sabin has secured funding to support the R&D program. The Biomedical Advanced Research and Development Authority (BARDA) within the U.S. Department of Health and Human Services awarded Sabin a development contract in September 2019, valued at up to $128 million. Under the terms of the funding agreement, the initial $20.5 million award supports process development and non-clinical activities. In May 2020, BARDA exercised the first two options of the contract, valued at $20 million. This second $20 million award will enable the manufacture and release of clinical vaccine material developed by ReiThera, a specialist in the development and cGMP manufacture of adenoviral vector vaccines. The funding will also support non-clinical studies to evaluate efficacy and immune response.
About Ebola Zaire, Ebola Sudan and Marburg

Ebola Zaire, Ebola Sudan and Marburg are members of the Filoviridae family, commonly referred to as filoviruses. Filoviruses are typically spread from wild animals – particularly fruit bats – to people, where transmission is continued through human-to-human contact. Though Marburg and Ebola are caused by different viruses, they manifest with clinically similar symptoms. Both can cause severe hemorrhagic fever in humans and nonhuman primates, with subsequent death in up to 90 percent of human cases.

Marburg was the first filovirus to be recognized in 1967 when a number of laboratory workers, including some in Marburg, Germany, developed hemorrhagic fever. Ebola was identified in 1976 when two simultaneous outbreaks occurred in northern Zaire (now the Democratic Republic of Congo, or DRC) in a village near the Ebola River and southern Sudan. The outbreaks involved what eventually proved to be two different species of Ebola virus; both were named after the nations in which they were discovered.

The 2014-2016 outbreak in West Africa, the largest Ebola outbreak in history, was caused by Ebola Zaire, starting in Guinea and then crossing borders to Sierra Leone and Liberia. The outbreak spread to 10 countries and took the lives of more than 11,000 people. Ebola Zaire also caused the 2018-2019 outbreak in the DRC, which has claimed thousands of lives and was declared a Public Health Emergency of International Concern by the World Health Organization in July 2019, an action reserved for the most severe global health threats.

For more information on the ongoing 2018-2019 Ebola Zaire outbreak, refer to the World Health Organization’s Ebola Situation Report.

Visit the World Health Organization’s website to read more about Ebola (Zaire and Sudan) and learn more about Marburg.

Why We Need Vaccines 

These viruses can spread to others through close personal contact or contact with bodily fluids. Currently, surveillance and isolation of infected people are the centerpieces of filovirus control. As there are no existing treatments for hemorrhagic fevers caused by filoviruses, primary prevention tools, such as effective vaccines, are of the utmost importance.

Experimental Ebola Zaire vaccines are being used in the ongoing outbreak in DRC, in a “ring strategy.” The importance of having multiple vaccines available during an outbreak is made clear when we consider what could happen to the vaccine supply should the situation worsen. As vaccines take time to produce, having other options ready can ensure greater stability of the global vaccine supply for use in emergencies. Sabin’s new agreements to continue development of GSK’s ChAd3 Ebola and Marburg vaccines show promise to further close the gap in the prevention of these diseases. Sabin supports all potential interventions to prevent illness and death caused by Ebola and Marburg, including new treatments, diagnostics and preventive measures.