Ebola Vaccines

Last Reviewed
March 4, 2021

Ebola Vaccines

Ebola vaccines are administered to protect people from contracting Ebola virus disease (EVD), a viral hemorrhagic fever caused by ebolaviruses. Ebola vaccines include replication-deficient adenovirus vectors, replication-competent vesicular stomatitis (VSV), human parainfluenza (HPIV-3) vectors, and virus-like nanoparticle preparations.

Ervebo (rVSVΔG-ZEBOV-GP) is a recombinant, replication-competent Ebola vaccine.

Zabdeno and Mvabea Ebola vaccine therapy is a prime-boost vaccination approach.

Ad5-EBOV is an adenovirus type 5 vector-based Ebola virus disease vaccine.

Ebanga (mAb114) is a human monoclonal antibody for treating Zaire Ebolavirus infections in adults and children. Ebanga is a human IgG1 MAb targeted to the Zaire ebolavirus glycoprotein, available in a lyophilized form.

Ebola Vaccine History

On December 19, 2019, the U.S. Food and Drug Administration announced the approval of Ervebo for the prevention of EVD caused by Zaire ebolavirus in individuals 18 years of age and older. The permission was granted to Merck & Co., Inc. ERVEBO is a recombinant, replication-competent Ebola vaccine, consisting of a VSV, genetically engineered to express a glycoprotein from the Zaire ebolavirus to provoke a neutralizing immune response to the Ebola virus.

Between August 2018 and May 20, 2020, 303,905 people were vaccinated with Ervebo in the DRC

This report, published by the U.S. CDC on January 8, 2021, summarizes the Advisory Committee on Immunization Practices (ACIP) recommendations for using the rVSVΔG-ZEBOV-GP Ebola vaccine (Ervebo) in the USA. 

The ACIP recommends preexposure vaccination with Ervebo for adults aged ≥18 years in the U.S. population who are at highest risk for potential occupational exposure to Ebola virus species Zaire ebolavirus because they are responding to an outbreak of EVD, work as health care personnel at federally designated Ebola treatment centers in the United States, or perform as laboratorians or other staff at biosafety level 4 facilities in the United States.

On July 1, 2020, Janssen's Zabdeno and Mvabea Ebola vaccine therapy, a prime-boost vaccination approach for preventing infectious diseases, was granted authorization by the European Medicines Agency. Janssen’s Ebola vaccine regimen is specifically designed to induce long-term immunity against the Ebola virus in adults and children aged one year and above. Between October 2019 and April 10, 2020, 20,339 people received the 1st dose of this vaccine, and 9,560 of them received the 2nd booster vaccination.

CanSino Biologics's Ad5-EBOV Ebola vaccine received approval in China in October 2017. Ad5-EBOV is an adenovirus type 5 vector-based Ebola virus disease vaccine that protects against Ebola by relying on the recombinant replication-defective human adenovirus type-5 vector immune response.

Ad5-EBOV is manufactured as a lyophilized powder, highly stable, and does not require storage at ultra-low temperatures. This feature renders it viable for use in resource-limited tropical areas.

The WHO published the revised Ebola Vaccine FAQ on January 11, 2020. And the U.S. CDC published 'Ebola Vaccine: Information for U.S. Healthcare Providers' on November 12, 2020.

International Coordinating Group on Vaccine Provision

Leading international health and humanitarian organizations announced a global Ebola vaccine stockpile to ensure outbreak response. The ICG was created as an additional tool to help control Ebola outbreaks. As Ebola outbreaks are relatively rare and unpredictable in nature and due to limited vaccine quantities, the current Ervebo vaccine is reserved for outbreak response. An initial 6,890 doses will be made available on a priority basis for outbreak response starting January 12, 2021.

To request access to ICG stocks, national or international health authorities should submit an application form to the ICG Secretariat (based at WHO Geneva) or an ICG member agency (IFRC, MSF, UNICEF, WHO) present in the country.

Ebola Outbreak in Western - Central Africa During 2021

March 3, 2021 - Since the last brief (23 February 2021), 11 new confirmed cases, one new death, and two new recoveries of Ebola virus disease (EVD) have been reported in Nzérékoré, Guinea, and North Kivu, Democratic Republic of Congo (DR Congo). This represents a 47% increase in the total number of cases reported this week than the last brief. Cumulatively, 28 EVD cases, 11 deaths (CFR: 39%), and two recoveries have been reported from DR Congo (11 cases; 4 deaths; 2 recoveries) and Guinea (17; 6; 2). Seven healthcare workers are amongst the confirmed cases: DR Congo (2) and Guinea (5).

February 26, 2021 - The U.S. CDC reported the U.S. government would funnel travelers from DRC and Guinea to six U.S. airports. Airlines will collect and transmit passenger information to the CDC for public health follow-up and intervention for all passengers boarding a flight to the U.S. in DRC or Guinea within the previous 21 days. Passengers can expect verification of data on arrival to ensure completeness and accurateness of contact information. This information will be shared with U.S. state and local health departments to monitor arrivals in their jurisdiction appropriately.

February 25, 2021 - The WHO reported nine cases, including five deaths had been reported in Guinea. While no confirmed Ebola cases have been recorded outside of the country, six nations bordering Guinea are finalizing their national preparedness and readiness operational plans according to a WHO readiness assessment tool. The overall state of readiness in the six countries is nearly 66% which is still lower than the benchmark of 80%. 

February 23, 2021 - The WHO announced the vaccination began in Guinea after receiving more than 11,000 doses of Merck's Ervebo rVSV-ZEBOV Ebola vaccine from its headquarters in Geneva. The WHO is also organizing the deployment of over 8,500 doses received directly from Merck in the initial phase of immunization.

February 22, 2021 - The WHO African Region tweeted, 'A supply of over 11,000 #Ebola vaccines sent by @WHO arrived in Conakry airport, #Guinea. The cargo was transported from Senegal by government plane after bad weather caused a stop-over in Dakar. Timely vaccination will be crucial in curbing the Ebola outbreak.'

February 18, 2021 - The World Health Organization announced it was deploying teams of experts to support the national authorities ramp up the response and avert widespread infections. In Guinea, health authorities declared an Ebola outbreak on 14 February after three cases detected in Gouécké, a rural community in N’Zerekore prefecture, tested positive for the virus. It is the first Ebola outbreak in Guinea since 2016, when a large one was successfully brought under control. More than 100 WHO staff, deployed from other countries and from within Guinea, are expected to be part of the Ebola response by the end of February 2020. Meanwhile, in the DRC, so far, there are four confirmed Ebola cases, including two deaths that are epidemiologically linked. WHO has around 20 experts supporting national and provincial health authorities. About 8,000 vaccine doses were still available in the country at the end of the 11th Ebola outbreak. The vaccination of people at high risk was officially launched in Butembo, the outbreak’s epicenter, on 15 February. So far, nearly 70 people have been vaccinated.

February 18, 2021 - The WHO reported, 'With efforts gathering pace to promptly tackle the new Ebola outbreaks in Guinea and the Democratic Republic of the Congo (DRC), the WHO is deploying teams of experts to support the national authorities ramp up the response and avert widespread infections. A consignment of more than 11,000 doses of the Ebola vaccine is expected to arrive in Guinea this weekend. Also, more than 8,500 doses will be shipped from the United States of America for a total of 20,000 doses. A 30-strong vaccination team has already been mobilized locally and is ready to deploy as soon as the vaccines are received.

February 16, 2021 - The WHO Weekly Bulletin focuses on public health emergencies occurring in the WHO African Region. In Guinea, health authorities declared an outbreak of Ebola virus disease (EVD) on 14 February 2021 in the rural community of Gouéké in N’Zerekore prefecture after the national laboratory confirmed three cases. Initial investigations found that a nurse from a local health facility had died on 28 January 2021 after presenting with headache, fatigue, nausea, vomiting, abdominal pain, and a temperature of 38ºC, after an initial diagnosis of malaria on 23 January 2021. She was buried on 1 February 2021 in Gouéké. So far, a total of seven cases have been reported, with three deaths (case fatality ratio 42.9%). Gueckedou and Conakry's laboratories have tested three more samples, where results returned positive for the Ebola virus. All had attended the nurse’s burial.

February 16, 2021 - The Africa CDC Tweeted that Guinea's Ebola outbreak total has now climbed to 17 cases, with five people dying from the disease. Sixteen cases are from N'Zerekore prefecture in the country's southeast, where the initial cases were reported. And the number of Ebola cases in the Democratic Republic of the Congo remains at four, including two fatalities.

February 16, 2021 - Mark Lowcock, the Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator Tweeted, 'Today I am allocating $15 million from @UNCERF to respond to the Ebola outbreaks in Guinea and the DRC. The funding will help these countries respond to the outbreak and support neighboring countries to prepare.

February 15, 2021 - The WHO African Region Tweeted:#Ebola vaccination campaign officially launched in #Butembo #DRC — just one week after the virus's resurgence. Health workers at Matanda health center, where the first Ebola patient was treated, were the first to be vaccinated. Furthermore, Doctors Without/Médecins Sans Frontières announced it is rapidly putting together an Ebola team in Guinea to support the Ministry of Health's Ebola response.

February 15, 2021 - The UN World Health Organization (WHO) announced the new Ebola cases were confirmed by the national laboratory, which occurred in Gouéké in N’Zerekore prefecture, in southern Guinea. Initial investigations found that a nurse from a local health facility died on January 28, 2021. Following her burial, six people who attended the funeral reported Ebola-like symptoms, and two of them later died. The other four are in hospital. Guinea was one of the three most-affected countries in the 2014-2016 West Africa Ebola outbreak, which was the largest since the virus was first discovered in 1976. Michel Yao, Ph.D., director of strategic health operations, said the samples belong to the Zaire subtype, the same one that fueled the earlier West Africa outbreak. That Ebola outbreak, which saw some 28,000 cases, including 11,000 fatalities, started in Guinea and then moved across land borders to Sierra Leone and Liberia in western Africa.

February 14, 2021 - Local media (CGTN Africa) reported the Democratic Republic of Congo confirmed the fourth Ebola case in North Kivu province. The WHO stated it is already working with health authorities in Liberia and Sierra Leone to beef up community surveillance of patients in their border districts and strengthen their capacity to test for cases and conduct surveillance in health facilities. WHO is reaching out to Cote d’Ivoire, Mali, Senegal, and other countries at risk in the sub-region.

February 14, 2021 - Aljazeera reported three fatalities from Ebola hemorrhagic fever occurred in the southeastern region of Nzerekore, Guinea. Guinea is a country in West Africa, bordered on the west by the Atlantic Ocean. On March 23, 2014, the World Health Organization reported an Ebola Virus Disease (EVD) outbreak in the forested rural region of southeastern Guinea. Identifying these EVD cases marked the beginning of the West Africa Ebola epidemic, the largest in history.

February 12, 2021 - The Democratic Republic of Congo confirmed a third Ebola case in North Kivu province. Provincial health minister Eugene Nzanzu Salita said, "We are in a meeting to gather all the information on the investigations done around this case," said Salita. The recent outbreak would be DRC's 12th Ebola outbreak.

February 11, 2021 - NPR reported a second person who had contracted the Ebola virus disease died in the Democratic Republic of Congo (DRC). The latest victim was from the North Kivu province, the World Health Organization and the DRC's health ministry said in a statement.

February 10, 2021 - The WHO reported, 'The resurgence is not unexpected given that EVD is endemic in the Democratic Republic of the Congo and that Ebola virus is present in animal reservoirs in the region. The risk of re-emergence through exposure to animal hosts or bodily fluids of Ebola survivors cannot be excluded. It is also not unusual for sporadic cases to occur following a major outbreak. WHO recommends providing medical care, psychological support, and biological testing (until two consecutive negative tests) through an EVD survivors care program to reduce the risk of transmission from virus persistence in some survivors' body fluids. WHO does not recommend isolation of male or female convalescent patients whose blood has been tested negative for the Ebola virus.

February 7, 2021 - The Minister of Health of the Democratic Republic of the Congo declared an outbreak of Ebola Virus Disease (EVD) after the laboratory confirmation of one case in North Kivu Province. The case was an adult female living in Biena Health Zone. More than 70 people who came into contact with the dead woman have been tracked, and the places she visited are being disinfected, said the World Health Organization, which is helping with the response.

Ebola Vaccine News

February 10, 2021 - In this study published by PLOS, researchers observed that EBOV RNA persistence in semen was a frequent phenomenon, with high population rates over time. This finding will inform forthcoming updated recommendations on risk reduction strategies relating to sexual transmission of EBOV. These findings support the implementation of a semen testing program as part of epidemic preparedness and response. Further, the results will enable planning of the magnitude of testing and targeted counseling needs over time.

February 3, 2021 - The Democratic Republic of the Congo (DRC) Crisis Response Plan 2021. The International Organization for Migration (IOM), in collaboration with its partners and other crisis response actors, seeks to provide urgently needed multisectoral humanitarian assistance, stabilization, and recovery support to conflict-affected populations in the DRC. IOM will also continue to support the government in responding to the COVID-19 pandemic and post-Ebola stabilization efforts and strengthening preparedness for future public health hazards. Considering the many requests for accurate displacement data in the DRC, IOM also aims to expand the scope of its Displacement Tracking Matrix interventions to cover the entire country, including monitoring population mobility to inform the outbreak preparedness and response.

January 29, 2021 - Ebola Situation Report #37: Democratic Republic of the Congo (DRC) - The Ebola outbreak in the northeast of the DRC, the country’s 10th and second-largest in world history, claimed the lives of 2,287 of the 3,324 patients affected. The 11th outbreak in Équateur Province affected 13 of the province’s 18 health zones, with 130 confirmed cases and 55 deaths. The introduction of an Ebola vaccine in the DRC in 2018 enabled the country to mitigate the last three outbreaks' impact. About 372,800 people have been vaccinated against Ebola (including 39,859 in Équateur province).

January 27, 2021 - Study: Ebola virus antibody decay–stimulation in a high proportion of survivors. The highest antibody reactivity was observed around 200 days after an individual had recovered. The model suggests that EBOV antibody reactivity declines over 0.5–2 years after recovery. In a high proportion of healthy survivors, antibody responses undergo rapid restimulation. Vigilant follow-up of survivors and possible elective de novo antigenic stimulation by vaccine immunization should be considered to prevent EBOV viral recrudescence in recovering individuals and mitigate the potential risk of reseeding an outbreak.

January 12, 2021 - A global emergency stockpile of 500,000 doses of Ebola vaccine, funded by Gavi, will be available to all countries for outbreak response following a procurement process concluded by UNICEF with a vaccine manufacturer. Gavi-eligible low- and lower-middle-income countries will access the stockpile free of charge. They will receive support for operational costs to conduct outbreak response immunization activities. The reserve will include licensed doses of the Ebola vaccine manufactured by MSD, known as Merck, inside the United States of America and Canada, which has received approval from the European Medicines Agency and the U.S. Food and Drug Administration, in addition to prequalification from WHO. The first deliveries of doses into the stockpile are funded through a $20 million contribution from the United States Agency for International Development, committed in 2017 and dedicated to supporting a supply of licensed Ebola vaccines to help tackle future disease outbreaks.

January 12, 2021 - The four leading international health and humanitarian organizations announced today establishing a global Ebola vaccine stockpile to ensure outbreak response. The supply will allow countries, with the support of humanitarian organizations, to contain future Ebola epidemics by providing timely access to vaccines for populations at risk during outbreaks. The injectable single-dose Ebola vaccine Ervebo (rVSV∆G-ZEBOV-GP, live) is manufactured by Merck and developed with financial support from the US government. The European Medicines Agency licensed the Ervebo vaccine in November 2019. The vaccine is now prequalified by WHO and approved by the US Food and Drug Administration and eight African countries.

December 22, 2020 - Early release study: Reston virus causes severe respiratory disease in young domestic pigs. We conclude that RESTV should be considered a livestock pathogen with zoonotic transmission impacting animals and perhaps even human health. Reston virus (RESTV), an ebolavirus, causes clinical disease in macaques but has only been associated with rare asymptomatic infections in humans.

December 3, 2020 - A study found 22.5% of healthcare workers (HCWs) had Ebola virus antibodies in their blood, even though only 15.1% reported contact with suspected, probable, or confirmed Ebola virus patients, in Boende, The Democratic Republic of the Congo. 'Our results provide additional evidence for asymptomatic or paucisymptomatic Ebola in the DRC and sub-Saharan Africa.'

November 18, 2020 - 11th Ebola outbreak in the Democratic Republic of the Congo declared over by the WHO. The episode in western DRC, announced on 1 June 2020, came as another Ebola outbreak in the eastern part of the country was winding down and finally declared over 25 June 2020. The two episodes were geographically far apart. Genetic sequencing analysis found that they were unrelated. By the end of the current 11th Ebola outbreak in Equateur Province, 119 confirmed cases, 11 probable, 55 deaths, and 75 people had recovered.

November 17, 2020 - The Lancet published a study: Vaccine innovation spurred by the long wait for an Ebola virus vaccine. Currently, the rVSV-based vaccine is used to immunize at-risk individuals during the ongoing Ebola virus outbreaks to limit the disease's spread. However, immunization of specific populations (e.g., health-care workers) in endemic countries outside of outbreak epicenters could reduce the likelihood of amplification from spillover events in humans.

November 12, 2020 - The U.S. CDC published Ebola Vaccine: Information for U.S. Healthcare Providers.

October 13, 2020 - A study published by The Lancet: Longitudinal antibody and T cell responses in Ebola virus disease survivors and contacts: an observational cohort study.

October 13, 2020 - In The Lancet Infectious Diseases, Ruth Thom and colleagues report substantial information concerning naturally acquired immunity following infection with Zaire ebolavirus.

October 11, 2020 - The 11th EVD outbreak in the Democratic Republic of the Congo has once again shown signs of slowing, with a few days with no new confirmed cases or deaths and one health zone with 42 days since the last confirmed case. However, this trend needs to be interpreted cautiously since there are still contacts lost to follow up, confirmed cases remain in the community, and safe and dignified burials continue to be a challenge. EVD awareness activities occur in tandem with COVID-19 response activities, which are to be commended. Hopefully, they will continue to help break the stigma associated with both diseases.

October 7, 2020 - A NEJM Perspective: Covid-19, Ebola, and HIV — Leveraging Lessons to Maximize Impact.

September 30, 2020 - Since the 11th Ebola outbreak began on June 1, 2020, 33,625 people have been vaccinated since the onset of the disease.

September 22, 2020 - Medscape Commentary: Who Should Receive the New Ebola Vaccine?

July 1, 2020 - J&J published '5 Latest Facts About Johnson & Johnson's Ebola Vaccine.'

June 26, 2020 - 10th Ebola Outbreak Ends as the 11th Ramps Up.

March 22, 2020 - Ebola Vaccination Recommended For At-Risk Healthcare Staff.

Ebola Antivirals

There are two antiviral treatments authorized to treat EVD, says the CDC

On October 14, 2020, the U.S. Food and Drug Administration (FDA) approved an antibody cocktail from Regeneron that's been shown to reduce Ebola-related mortality rates. The treatment is known as REGN-EB3, is a mixture of (3) monoclonal antibodies (atoltivimab, maftivimab, and odesivimab-ebgn), and is marketed under the brand name Inmazeb. Inmazeb is indicated for the treatment of infection caused by Zaire ebolavirus in adult and pediatric patients, including neonates born to a mother who is RT-PCR positive for Zaire ebolavirus infection.

On December 22, 2020, Ridgeback Biotherapeutics LP confirmed that the U.S. FDA approved Ebanga to treat Ebola. Ebanga is now approved to treat infections caused by Zaire ebolavirus in adult and pediatric patients.

Ebola History

Ebola virus, also known as Zaire ebolavirus, Sudan ebolavirus, and Bundibugyo ebolavirus, can cause severe hemorrhagic fever, leading to high case fatality rates (30–90%) in humans.

On August 11, 2014, the WHO convened a meeting and concluded an “ethical imperative” to develop experimental Ebola vaccines. West Africa is experiencing the largest, most severe, most complex Ebola virus disease outbreak in history.

Previous Ebola outbreaks have been contained by existing interventions, such as early detection and isolation, contact tracing and monitoring, and adherence to rigorous procedures of infection prevention and control. However, effective treatments and vaccines would dramatically strengthen the ability to counter the disease.

Using the groundwork laid by Yale scientists in the 1990s, the first-ever Ebola Zaire vaccine was recently approved by the European Commission.

"The Ervebo vaccine’s approval is the fruition of decades of research led by John Rose, Ph.D., a School of Medicine pathology professor emeritus, who developed a method to genetically engineer the harmless vesicular stomatitis virus, or VSV, to express proteins found on other viruses to build immunity without developing harmful symptoms. This was an 8-year endeavor in my lab at Yale,” Dr. Rose said in a Yale press release, published on December 3, 2019.

“We suspected that VSV, which is a type of RNA virus circulating among livestock that is harmless to humans, could be a very potent vaccine platform for numerous diseases, like influenza and HIV. The idea was to insert new genes from pathogens into VSV and use this genetically modified virus as a vaccine.”

When injected, the genetically modifiable virus developed by Dr. Rose’s group allows exposure to disease-causing proteins from a range of harmful viruses while circumventing illness. The body can build immunity to the harmless “mimickers” of infection.

In the case of the Ervebo vaccine, immune cells respond to Ebola surface proteins built onto VSV, and immunological memory can develop without making people sick because the VSV system poses no harm.

According to Dr. Rose, the genetically engineered VSV platform was not intended for treating a specific disease but rather to be modified for applications in numerous viral infections. After developing the VSV platform, Dr. Rose and his collaborators provided this system to over 100 labs, including one in Germany working on an Ebola vaccine.

RESTV is the only ebolavirus that has not shown any symptoms in humans, thus far only been seen in monkeys from the Philippines (being held in quarantine facilities in the United States and Italy) and on a pig farm in the Philippines.

Note:  Content Sources for this page include the World Health Organization, the US Centers for Disease Control and Prevention, clinicaltrials.gov, and the Precision Vaccinations news network.  Dr. Robert Carlson has reviewed this information.