Ebola virus disease vaccines
16 October 2025 | Questions and answersNote: These Q&As use the virus taxonomy approved in April 2023 by the Executive Committee of the International Committee of Taxonomy on Viruses.
Currently there are two licensed Ebola vaccines prequalified by WHO for Ebola virus disease (EVD) caused by Ebola virus (species Orthoebolavirus zairense).
- Ervebo® vaccine, administered in one dose.
- Zabdeno® and Mvabea® vaccine, administered in a two-dose regimen.
The Ervebo® vaccine is recommended for use in outbreak settings and is currently the only vaccine available in the global stockpile.
As part of outbreak response, a CORE protocol to evaluate the safety, tolerability, immunogenicity, and efficacy of vaccine candidates is available.
See the July 2024 WHO Strategic Advisory Group of Experts on Immunization (SAGE) recommendations for further information-
There are at least three species of orthoebolaviruses known to cause large outbreaks in humans:
- Ebola virus (EBOV) causing Ebola virus disease (EVD)
- Sudan virus (SUDV) causing Sudan virus disease (SVD)
- Bundibugyo virus (BDBV) causing Bundibugyo virus disease (BVD).
While there are only licensed vaccines for EVD, several candidate vaccines are at different stages of development.
The Ervebo vaccine has been used under “expanded access” or what is also known as “compassionate use” for 16 000 people in Guinea in 2015 and for 345 000 people during the 2018-2020 outbreaks in the Democratic Republic of the Congo.
The Zabdeno and Mvabea vaccine was studied in a total of 3 367 adults, adolescents and children who participated in 5 clinical studies conducted in Europe, Africa and the United States of America. These studies demonstrated that the vaccine regimen is safe and could induce an immune response against the Ebola virus. Efficacy data in humans has been extrapolated from animal studies. The exact level of protection provided by the vaccine regimen is not yet fully known.
Ervebo® is the only vaccine currently available for outbreak response. There is a global Ebola vaccine stockpile, managed by the International Coordinating Group (ICG) on vaccine provision. This stockpile allows WHO, countries and other partners to contain future EVD outbreaks by ensuring equitable and timely access to vaccines for populations most at risk during outbreaks.
When an outbreak of EVD is confirmed, countries can request vaccines through the ICG. The ICG will provide vaccines and operational cost support to eligible countries.
Those eligible for the Ebola vaccine during an outbreak are:
- all people who have come into direct or indirect contact with a confirmed or a probable case; and
- frontline and health-care workers because they are at the highest risk of contracting the disease during an EVD outbreak response. Included are clinicians and nurses who treat patients, surveillance and contact tracing teams, laboratory staff, safe burial teams, community workers, traditional healers, drivers and other community key stakeholders who are likely to interact with confirmed or probable cases.
Vaccination is an important component of outbreak response. The goal is to protect individuals at highest risk, using a ring vaccination or targeted geographic strategy.
In vaccine studies conducted since 2015, most of the adverse effects were typically mild. Vaccinated individuals most commonly reported headache, fatigue, muscle pain and mild fever.
A ring vaccination strategy is one that has been used to contain disease outbreaks by vaccinating the close contacts and potential contacts of a confirmed or probable case, creating a "ring" of immunity around a confirmed or probable case to prevent transmission.
Someone is listed as a contact when he/she has been in touch with the body fluids (blood, vomit, saliva, urine, faeces, breast milk) or shared the linens, clothes, or dishes/eating utensils of a person with a confirmed or probable status of Ebola disease.
Potential contacts are neighbours, family members, or extended family members at the closest geographic boundary of all contacts, plus household members of all contacts.
No vaccine is 100 percent effective. Persons who receive the vaccine should continue to protect themselves from Ebola virus infection by not touching a patient’s body (dead or alive), or bodily fluids, including blood, vomit, saliva, urine or faeces. Personal items used by the patient like bedding and clothes may also be contaminated with Ebola virus and should be avoided.
If a person receiving the vaccine was already infected with the Ebola virus before he/she was vaccinated, they could develop Ebola virus disease after they receive the vaccine. If they develop any symptom of illness, they should immediately contact the vaccination team.
A targeted geographic vaccination strategy involves vaccinating everyone in the neighbourhood, or village, rather than vaccinating only the known contacts and potential contacts. This approach can be used when the cases are contained within a small geographic area or when contact tracing is difficult (e.g. difficult to access areas or when contact tracing is not feasible as in poor security settings).
The Ervebo vaccine is indicated in individuals of 12 months of age and older.
However, the Strategic Advisory Group of Experts on Immunization (SAGE) recommends “off label” use in outbreak settings depending on risk factors including:
- children from birth
- pregnant and lactating women.
This means that each country should make the decision on whether or not to offer the vaccine to these categories of the population, based on their vulnerabilities and exposure to the risk of Ebola infection.
The Zabdeno and Mvabea vaccine regimen is also indicated for immunization in individuals over 12 months of age.
No, the vaccines do not contain live virus and it is not possible to be infected with Ebola as a result of vaccination.
People who survive EVD usually develop some natural protection against the disease. This protection is believed to last for several years, although it may slowly decrease over time.
Ebola disease survivors are encouraged to apply all the protective measures against Ebola disease, including vaccination.
Ring vaccination is a strategy to vaccinate individuals at highest risk of infection due to their connection to a patient confirmed with the virus.
When a patient is laboratory confirmed, the definition of the vaccination ring is made as follow:
- Contacts are defined as individuals who, in the last 21 days, lived in the same household, were visited by the patient after they developed symptoms, or visited the patient or were in close physical contact with the patient's body, body fluids, linen or clothes.
- Contacts of contacts are defined as neighbours, family, or extended family members at the closest geographic boundary of all contacts, plus household members of all contacts who do not live in the same locality as the patient.
- SAGE also recommends vaccinating health care workers and frontline workers responding to the outbreak who may be in contact with Ebola patients.
The ring is not necessarily a contiguous geographic area but captures a social network of individuals and locations that may include dwellings or workplaces further afield where the index patient spent time while symptomatic, or the households of individuals who had contact with the patient during the illness or after his or her death. Experience suggests that each ring may be composed of an average of 150 persons.
Vaccination against Ebola virus disease provides individual and collective immunity that reduces the harmful effects of the disease, including severe illness and death.
Unvaccinated persons have a high risk of dying in case of infection and increase the risk of the spread of the virus within the community.
It is important to ensure that all people at immediate risk of Ebola virus infection are immunized to protect themselves and others.
Most common side effects associated with Ebola virus disease vaccines are mild and occur within 24-48 hours of being vaccinated.
After receiving the EVD vaccine, people can experience:
- injection site pain
- fever
- headache.
Symptoms will generally disappear within 24 hours of onset.
According to evidence it takes between 10 and 14 days to develop a complete immune response. This means that a person can still get infected before the vaccine provides full protection.
Vaccines are not 100% effective. People vaccinated against Ebola can still be infected even when the vaccine has provided immunity in the body, and has provided good protection against a severe form of Ebola and even death. Furthermore, not all individuals respond to the vaccines in the same manner.
If a person receiving the vaccine was already infected with the Ebola virus before he/she was vaccinated, they could develop Ebola virus disease after they receive the vaccine. If they develop any symptom of illness, they should immediately contact the vaccination team.
People who have received the vaccine should continue to protect themselves.
They should avoid touching a patient’s body (dead or alive), or their body fluids, including blood, vomit, tears, saliva, urine or faeces, as well as the patient’s personal items such as bedding and clothes.
No, it is not possible to be infected with Ebola as a result of vaccination. The vaccine does not contain live virus.
Antibodies to the virus have been detected up to four years after vaccination. However, it is not known whether this level of antibodies is enough to protect against Ebola infection. Therefore, revaccination is recommended for anyone at high risk during an outbreak if they have not received an Ebola vaccine in the last six months.
There is no data available regarding receipt of a subsequent dose of an Ebola vaccine that is different to the one originally received.
Research is ongoing to learn more about booster doses of licensed Ebola vaccines.
Vaccination is just one component of a strategy to control an Ebola outbreak. Other important components include:
- early detection of new Ebola infections through active surveillance;
- functional laboratory services to confirm Ebola infections;
- separating (isolating) patients to prevent further spread at home or in the community and to provide safe and supportive care;
- safely and respectfully burying the dead to reduce further spread of Ebola virus through contact with deceased patients; and
- systematically engaging communities from the start in the Ebola response.