Ebola viruses
Ebola viruses belong to the Filoviridae family of filamentous, negative-stranded RNA, enveloped viruses consisting of three genera: Ebola virus (EBOV), Marburg virus and Cueva virus. There are five distinct species of EBOV: Zaire ebolavirus (ZEBOV), Sudan ebolavirus (SUDV), Tai Forest ebolavirus (TAFV), Reston ebolavirus (RESTV) and Bundibugyo ebolavirus (BDBV). The Ebola virus causes an acute, serious illness which is often fatal if untreated. Ebola virus disease (EVD) formerly known as Ebola haemorrhagic fever, is a severe, often fatal illness in humans. The virus causing the 2014–2016 West African outbreak belongs to the Zaire ebolavirus species.
Ebola Vaccines
A large number of candidate Ebola vaccines are under development. Some of these vaccines had already been in preclinical development prior to the 2014–2016 EVD epidemic and are significantly more advanced than the others. To date, several candidate vaccines (including monovalent, bivalent and multivalent candidate vaccines) have undergone or are undergoing clinical development at different trial phases. The most advanced Ebola vaccines are based on live recombinant virus vector platforms. Development of Ebola vaccine is being monitored by WHO Strategic Advisory Group of Experts (SAGE) Working Group on Ebola Vaccines and Vaccination. Examples of Ebola vaccines currently under clinical development are provided in a WHO Working Group background paper.
Ebola Vaccine Standardization
Written standards
The unprecedented scale and severity of the EVD epidemic in West Africa in 2014–2016 led to calls for the urgent development and licensing of an Ebola vaccine. A considerable amount of work was subsequently undertaken and a series of international consultations held on related public health issues and on Ebola vaccine development, evaluation and licensing. As part of ongoing WHO measures to support the development of Ebola vaccines and as a result of series of informal and public consultations with stakeholders during 2015-2017, Guidelines on the quality, safety and efficacy of Ebola vaccines have been developed and approved by the WHO Expert Committee on Biological Standardization at its 68th meeting in October 2017.
These WHO Guidelines provide scientific and regulatory guidance for national regulatory authorities and vaccine manufacturers on the quality, nonclinical and clinical aspects of Ebola vaccines relevant to marketing authorizations. In particular, the document deals with Ebola vaccines based on viral vectors, which are currently at the most advanced stage of development and for which no specific WHO guidance is available. The document also discusses opportunities to accelerate vaccine development and product availability during a public health emergency.
It should be noted that there remain knowledge gaps in the scientific understanding of EVD and Ebola vaccines which are being addressed by ongoing research and development. This document has been developed in the light of the available knowledge to date, and with regard to the currently most advanced candidate Ebola vaccines.
Guidelines on the quality, safety and efficacy of Ebola vaccines, WHO TRS 1011, Annex 2
Measurement standards
International reference preparations were developed for the standardization of assays for Ebola including immune assays and nucleic acid assays through international collaborative efforts. These preparations were established by WHO ECBS at its meetings in 2015, 2016, and 2017 as WHO Reference Reagents or International Standards.
All the reference materials are available from the National Institute for Biological Standards and Control, Potters Bar, the United Kingdom. For the latest list of appropriate WHO international standards and reference materials, the WHO Catalogue of International Reference Preparations should be consulted.
Prequalified Ebola vaccines
From March 2016 there is a new system for display of WHO prequalified vaccines
Find out more about the new listing and how to search and display the list on the link below