Ebola Virus Disease Vaccines

Ebola Virus Disease (EVD) is caused by one of five species of Ebola viruses, namely, Zaire, Sudan, Tai Forest, Bundibugyo and Reston, with the most fatal specie being the Zaire virus (REF). Over the years, there have been several outbreaks in Zaire, Democratic Republic of Congo, Uganda, Sudan, Gabon and Congo. The last major outbreak occurred in 2014‐2015 in countries of West Africa subregion, mainly in Liberia, Guinea and Sierra Leone and to a lesser extent in Nigeria and Mali. This was the largest EVD outbreak to date, and a total of 28,646 Ebola cases were reported in the three most affected countries (Guinea, Liberia and Sierra Leone), with 11,323 deaths. A significant proportion of survivors have both short‐ and long‐term sequelae.

In order to facilitate potential submissions as well as the assessment process under an emergency use listing procedure, WHO had exceptionally decided to accept “rolling on submissions” when the manufacturers can submit data sets as they become available. The SAGE working group on EVD Vaccines and Vaccination, held on 14–15 March 2017, recommended that the use of the rVSVΔG‐ZEBOV‐GP candidate vaccine should be deployed under the Expanded Access framework.

In May 2019, WHO published a roadmap aiming to coordinate partners’ actions and contributions to the licensing and roll-out of Merck’s Ebola vaccine (VSV-ZEBOV) in African countries. The vaccine was developed during the West Africa Ebola epidemic of 2014-2016, during which more than 11 000 people lost their lives to the disease. The vaccine was tested in European and African countries at the time and was used under an “expanded access” protocol in the Democratic Republic of Congo.

Based on regulatory evaluation by European Medicines Agency and the US Food and Drug Administration, WHO expedited prequalification and coordinated work with countries at risk of Ebola outbreaks to streamline regulatory licensing of the vaccine for use in those countries.

Ervebo vaccine prequalified

On 12 November 2019, WHO prequalified an Ebola vaccine for the first time, a critical step that will help speed up its licensing, access and roll-out in countries most at risk of Ebola outbreaks. This is the fastest vaccine prequalification process ever conducted by WHO. The injectable Ebola vaccine, Ervebo, is manufactured by Merck (known as MSD outside the US and Canada). The vaccine has been shown to be effective in protecting people from the Ebola Zaire virus and is recommended by the WHO Strategic Advisory Group of Experts (SAGE) for vaccines as part of a broader set of Ebola response tools. The decision is a step towards greater availability of the vaccine in the future, though licensed doses will only be available mid-2020.

WHO publishes roadmap for introduction roll out of second Ebola vaccine

In February 2020, WHO published a roadmap aiming to coordinate partners’ actions and contributions to the licensing and roll-out of Janssen’s Ebola vaccine (Ad26.ZEBOV, MVA-BN®-Filo) in African countries. This second vaccine was developed during the West Africa Ebola epidemic of 2014-2016, during which more than 11 000 people lost their lives to the disease. The vaccine was tested in European and African countries at the time. WHO will expedite prequalification and licensing of the vaccine for use in countries at risk of Ebola outbreaks and will coordinate work between those countries’ regulatory authorities and the European Medicines Agency and the US Food and Drug Administration.