Vaccine Info

Ervebo Ebola Vaccine

Last Reviewed
February 24, 2021

Ervebo (rVSV-ZEBOV) Ebola Vaccine Description

Ervebo, Ebola Zaire Vaccine, Live, formerly known as V920, (rVSV-ZEBOV-GP), is a recombinant, replication-competent Ebola vaccine, consisting of a vesicular stomatitis virus (VSV), which has been genetically engineered to express a glycoprotein from the Zaire ebolavirus to provoke a neutralizing immune response to the Ebola virus.

Merck's Ervebo vaccine's active ingredient is live Vesicular Stomatitis Virus, in which its surface protein has been replaced with that of Zaire ebola virus disease (EVD). Inactive ingredients include recombinant human serum albumin, tromethamine (Tris) buffer. This vaccine contains a trace amount of rice protein.

The Ervebo Ebola Zaire vaccine (live, attenuated), v920; rVSV-ZEBOV; Drugbank's Accession Number: DB15595. ATC code: J07BX02. This Merck vaccine is authorized for use in the European Union.

Ervebo (rVSV-ZEBOV) Ebola Vaccine History

On January 8, 2021, the U.S. CDC's Advisory Committee on Immunization Practices (ACIP) recommends the use of the rVSVΔG-ZEBOV-GP Ebola vaccine (Ervebo) in the United States for preexposure vaccination for adults aged ≥18 years in the U.S. population who are at the 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 work as laboratorians or other staff at biosafety level 4 facilities in the United States.

The U.S. FDA granted this application Priority Review and a Tropical Disease Priority Review Voucher on September 17, 2019. The FDA also granted Breakthrough Therapy designation for Ervebo to facilitate the vaccine's development and scientific evaluation. And on December 19, 2019, the FDA announced the approval of Ervebo, the first FDA-approved vaccine for preventing Ebola virus disease (EVD) caused by Zaire ebolavirus in individuals 18 years of age and older.

On January 12, 2021, leading international health and humanitarian organizations announced 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 included.

Merck announced on February 15, 2020, that 4 African countries, including the Democratic Republic of the Congo, Burundi, Ghana, and Zambia, have approved the use of Ervebo.

Since the beginning of the Ervebo vaccination program in central Africa in 2019, approximately 300,000 persons have been vaccinated with the ERVEBO vaccine. Merck is working to initiate the manufacturing of licensed vaccine doses and expects these doses to become available in approximately the 3rd quarter of 2020.

The Joint Project Manager for Chemical, Biological, Radiological, and Nuclear Medical (JPM-CBRN) helped provide a test that allowed Merck to test human and non-human primate samples. Comparing the two samples is part of the FDA’s requirements for licensure.

Merck & Co. Inc. licensed the global R&D and manufacturing rights from Newlink Genetics Corp.'s phase I Ebola vaccine in 2014. The Public Health Agency of Canada, which originally developed the vaccine, retained noncommercial rights in the agreement.

Ervebo (rVSV-ZEBOV) Ebola Vaccine Indication

The Ervebo vaccine (rVSV-ZEBOV-GP) is indicated to prevent disease caused by Zaire ebolavirus in individuals 18 years of age and older. The duration of protection conferred by Ervebo is unknown, and it does not protect against other species of Ebolavirus or Marburgvirus. When administered concurrently with antiviral medication, the vaccine's effectiveness, immune globulin (IG), and/or blood or plasma transfusions are unknown.

People cannot get the Ebola virus disease from the Ervebo vaccine.

Ebola cases are sporadic in the U.S., and those that have occurred have been the result of infections acquired by individuals in other countries who then traveled to the U.S. or health care workers who became ill after treating patients with EVD. In September 2014, a man arrived in Dallas, Texas, infected with Ebola, and was treated at a local hospital. This person passed the virus to the healthcare staff.

Ebola virus can be detected in blood after the onset of symptoms. It may take up to 3 days after symptoms start for the virus to reach detectable levels. The CDC’s new Health Alert recommends that Ebola virus testing be conducted only for people who have an epidemiologic risk factor within 21 days of symptom onset and who have an Ebola-compatible clinical syndrome.

Following vaccination with the Ervebo vaccine, individuals may test positive for anti-Ebola glycoprotein (GP) antibody and/or Ebola GP nucleic acid or antigens. GP-based testing may have limited diagnostic value during vaccine viremia, in the presence of vaccine-derived Ebola GP, and following antibody response to the vaccine.

A polymerase chain reaction is one of the most commonly used diagnostic methods because of its ability to detect ebola virus disease, says the CDC. 

As of January 12, 2021, the vaccine was administered to more than 350,000 people in Guinea and the 2018-2020 Ebola outbreaks in the Democratic Republic of the Congo under a protocol for “compassionate use.”

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.

Ervebo (rVSV-ZEBOV) Ebola Vaccine Efficacy 

Vaccine efficacy was evaluated in a two-part phase 3, open-label, cluster-randomized, controlled ring vaccination trial in Guinea during the 2014–2016 Ebola outbreak in West Africa, says the CDC.

In the initial study, clusters of contacts of confirmed EVD patients and contacts of those contacts were offered immediate vaccination or delayed vaccination (21 days after randomization). The primary outcome of interest was the incidence of laboratory-confirmed EVD with onset ≥10 days after randomization. The 10-day period was selected to account for the incubation period of EVD and the unknown length of time from vaccination to protective immunity development.

Analysis of the randomized clusters in the initial study demonstrated that among the 2,108 participants vaccinated immediately, none developed EVD ≥10 days after randomization. In the delayed group, 10 of 1,429 participants developed EVD ≥10 days after randomization. Based on the cluster-level data, vaccine efficacy in the initial study was calculated to be 100% (95% CI: 63.5%–100%) in participants receiving immediate vaccination.

The follow-up study included additional data about clusters of contacts and contacts of contacts who were offered immediate vaccination. Analysis of the randomized and nonrandomized clusters in the follow-up study demonstrated that no one immediately vaccinated (0 of 3,775 participants) developed EVD ≥10 days after randomization (or for nonrandomized participants, the date of inclusion in the ring). In the delayed or never-vaccinated group, 23 of 4,507 participants developed EVD ≥10 days after randomization.

Based on cluster-level data, vaccine efficacy in the follow-up study was calculated to be 100% (95% CI: 79.3%–100%).

Overall, the CDC states the rate of pregnancy loss among pregnant women who received immediate vaccination was not statistically significantly higher than the rate of pregnancy loss among unvaccinated pregnant women. No external congenital anomalies were detected among live-born infants in either group (n = 44).

Ervebo (rVSV-ZEBOV) Ebola Vaccine Dosage

The Ervebo vaccine (rVSV-ZEBOV-GP) is administered as a single-dose intramuscular injection. You will get this vaccine as an injection at the top of your arm.

Merck says, 'do not administer Ervebo to individuals with a history of a severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine, including rice protein.' The safety and effectiveness of Ervebo have not been assessed in immunocompromised individuals.

There are no adequate and well-controlled studies of Ervebo in pregnant women. Human data available from clinical trials with Ervebo are insufficient to establish the presence or absence of vaccine-associated risk during pregnancy. The decision to vaccinate a pregnant woman should consider the woman’s risk of exposure to Zaire ebolavirus.

Furthermore, previous clinical studies of Ervebo did not include sufficient numbers of subjects 65 years of age and older to determine whether they respond differently from younger subjects.

International Coordinating Group on Vaccine Provision - Ebola vaccine stockpiles

The ICG manages the Ebola vaccine's global stockpile, which 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 to protect people at the highest risk of contracting Ebola – including health care and frontline workers in an outbreak – under a ring vaccination strategy. An initial 6,890 doses will be made available on a priority basis for outbreak response starting 12 January 2021.

Depending on the rate of vaccine deployment, it could take 2 to 3 years to reach the SAGE-recommended level of 500 000 doses for emergency stockpiles of vaccines. WHO, UNICEF, Gavi, and vaccine manufacturers continuously assess options to increase vaccine supply in case global demand increases.

The ICG is working with partners and stakeholders to use the Ervebo outbreak response vaccine in the context of an integrated Ebola outbreak response strategy based around early detection, contact tracing, case management, infection prevention and control measures, safe and dignified burials, and raising awareness among the affected communities.

    Ervebo (rVSV-ZEBOV) Ebola Vaccine News

    February 23, 2021 - The Ebola disease vaccination program began in Guinea after receiving about 11,000 doses of Merck's Ervebo rVSV-ZEBOV vaccine from the WHO's headquarters in Geneva. The WHO is also deploying over 8,500 vaccine doses received directly from Merck.

    February 18, 2021 - The VOA reported speaking in a virtual news conference from her headquarters in Brazzaville, Republic of Congo, WHO Africa Director Matshidiso Moeti said officials are also expecting an additional 8,600 doses of vaccine from the United States, for a total of nearly 20,000 shots. She expects them to arrive by Sunday and Ebola vaccinations to begin by Monday.

    February 15, 2021 - 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. 'We will try to get the right balance between responding quickly and taking steps to ensure the community is a willing and active participant in both prevention and response. Alongside treatment for Ebola, contact tracing and other community-based activities will be absolutely vital.'

    February 15, 2021 - BBC reported about 8,000 doses of the Ervebo vaccine, which were kept after the outbreak, are being used in the latest inoculation campaign, the BBC's Emery Makumeno reports from the capital Kinshasa. Ervebo was the first Ebola vaccine to be approved by the US Food and Drug Administration in December 2019.

    February 12, 2021 - Media reports indicate the DRC 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." The recent outbreak would be DRC's 12th Ebola outbreak. The health ministry and the WHO said in a statement, '1,200 doses of Ebola vaccine and cold chain equipment arrived in Butembo.'

    February 11, 2021 - The BBC reported Eugene Nzanzu Syalita, a DRC health minister, indicated the country would start inoculating people in Masaya, a heath zone near Butembo. In total, 161 people in that area had been traced to the first Ebola patient.

    February 7, 2021 - The Ministry of Health of the Democratic Republic of the Congo (DRC) announced that a recent Ebola case had been detected in Butembo, a city in North Kivu Province, where a previous outbreak was declared over in June 2020. The Butembo branch of the National Institute of Biomedical Research confirmed Ebola in samples taken from a patient with Ebola-like symptoms who had sought treatment at a local health center. The woman was the wife of an Ebola survivor. She has since died. Butembo was one of the epicenters of the previous Ebola outbreak (11th) in eastern DRC. It is not unusual for sporadic cases to occur following a major outbreak, says the WHO.

    January 29, 2021 - 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 - The journal Nature published a new 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 27, 2021 - The European Centre for Disease Prevention and Control published 'Treatment and vaccines for Ebola virus disease.'

    January 12, 2021 - United Nations agencies and humanitarian partners announced a global Ebola vaccine stockpile to help control future epidemics by ensuring timely access to vaccines for populations at risk during outbreaks. 

    January 8, 2021 - This CDC report summarizes the Advisory Committee's recommendations on Immunization Practices to use the rVSVΔG-ZEBOV-GP Ebola vaccine (Ervebo) in the United States. The vaccine contains rice-derived recombinant human serum albumin and a live attenuated recombinant vesicular stomatitis virus (VSV). The gene encoding the VSV glycoprotein was replaced with the gene encoding the Ebola virus species Zaire ebolavirus's glycoprotein. Persons with a history of a severe allergic reaction (e.g., anaphylaxis) to rice protein should not receive Ervebo. This is the first and only vaccine currently licensed by the Food and Drug Administration to prevent Ebola virus disease.

    November 2, 2020 - More than 703 new people received the rVSV-ZEBOV-GP vaccine for a cumulative total of 40,065 people vaccinated in the DRC.

    September 30, 2020 - The U.S. CDC issued an Alert - Level 2, Practice Enhanced Precautions, for prospective visitors to central Africa's DRC area.

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

    June 26, 2020 - The World Health Organization marked the end of the 10th outbreak of Ebola virus disease in the Democratic Republic of the Congo. About 303,000 people were vaccinated with the ERVEBO is a recombinant, replication-competent Ebola vaccine.

    May 26, 2020 - Merck and IAVI announced a collaboration to develop an investigational vaccine targeted against the SARS-CoV-2 coronavirus. This vaccine candidate will use the recombinant vesicular stomatitis virus (rVSV) technology that is the basis for Merck’s Ebola Zaire virus vaccine, ERVEBO, which was the first rVSV vaccine approved for use in humans.

    May 6, 2020 - The Lancet: Pregnancy and breastfeeding in the context of Ebola: a systematic review.

    February 21, 2020 - National Health Authorities register ERVEBO vaccine in the Democratic Republic of Africa, Burundi, Ghana, and Zambia.

    February 14, 2020 - Merck confirmed that four African countries, including the Democratic Republic of the Congo, have approved the ERVEBO vaccine. ERVEBO has now been registered by National Health Authorities in the following countries in Africa – DRC, Burundi, Ghana, and Zambia. Approvals in additional countries in Africa are anticipated shortly, said Merck. As previously announced, Merck is working to initiate the manufacturing of licensed doses and expects these doses to start becoming available in approximately the third quarter of 2020.

    December 16, 2019 - In Health Advisory #423, the CDC says ‘there have been 49 travelers since August 2018 who were ill when returning to the USA from the Democratic Republic of Congo (DRC) or the surrounding African countries.

    December 19, 2019The U.S. Food and Drug Administration announced the approval of Ervebo, the first FDA-approved vaccine for the prevention of Ebola virus disease caused by Zaire ebolavirus in individuals 18 years of age and older. Ervebo was determined to be 100% effective in preventing Ebola cases with symptom onset more significant than 10 days after vaccination. No cases of EVD with symptom onset more significant than 10 days after vaccination were observed in the “immediate” cluster group, compared with 10 cases of EVD in the 21-day “delayed” cluster group.

    November 14, 2019 - The FDA granted Priority Review and a Tropical Disease Priority Review Voucher and granted a Breakthrough Therapy designation for the Ervebo vaccine.

    November 11, 2019The European Commission announced the granting of marketing authorization to Merck Sharp & Dohme B.V. for its Ebola Zaire vaccine. This announcement follows the European Medicines Agency (EMA), which has assessed the vaccine's benefits and risks. Formally known as v920 (rVSVΔG-ZEBOV-GP). Ervebo is a recombinant, replication-competent Ebola vaccine consisting of a vesicular stomatitis virus (VSV), genetically engineered to express a Zaire's glycoprotein ebolavirus to provoke a neutralizing immune response to the Ebola virus.

    November 6, 2019 - Dulles Airport adding staff to potentially screen passengers for infectious diseases such as Ebola.

    October 18, 2019 - The EMA’s human medicines committee (CHMP) has recommended granting a conditional marketing authorization in the European Union for Ervebo V920 (rVSVΔG-ZEBOV-GP),

    July 10, 2019 - The DRC’s Minister of Health decided that ‘due to the lack of sufficient scientific evidence on the efficacy and safety of other Ebola vaccine candidates, as well as the risk of confusion among the population, it was decided that no additional clinical vaccine trials will be allowed throughout the country.’  This means Merck's V920 will be the only Ebola Vaccine available in the DRC.

    June 17, 2019 - Houston, Texas, is an Ebola treatment team leader with physicians, nurses, medical technologists, and environmental experts.

    May 23, 2019The Ethics Committee of the School of Public Health of the University of Kinshasa approved the amendment of the compassionate belt vaccination protocol for the rVSV-ZEBOV vaccine to expand its targets to pregnant women after the first trimester and lactating women identified as contacts. It is maintained for minors that children can be vaccinated from 6 years. Between 26 November 2018 and 26 May 2019, 319 pregnant women and 603 lactating women registered as contacts could not be vaccinated.

    July 25, 2016 - Merck announced two regulatory milestones for its investigational vaccine for Ebola Zaire, V920 (rVSV∆G-ZEBOV-GP, live attenuated): the U.S. Food and Drug Administration has granted the vaccine candidate Breakthrough Therapy Designation, and the European Medicines Agency has granted PRIME status.

    December 23, 2015 - Merck announced the application for Emergency Use Assessment and Listing (EUAL) for its investigational Ebola Zaire vaccine, V920 (rVSV∆G-ZEBOV-GP, live attenuated), has been accepted for review by the World Health Organization.

    Ervebo Vaccine Clinical Trails

    Clinical Trial NCT02503202  Phase 3: Evaluation of the Safety and Immunogenicity of Three Consistency Lots and a High-Dose Lot of rVSV-ZEBOV-GP (V920 Ebola Vaccine) in Healthy Adults (V920-012).

    • This Phase 3 study evaluated the safety and immunogenicity of 3 consistency lots and a high-dose lot of rVSV-ZEBOV-GP (V920 Ebola Vaccine) in healthy adults. This study's primary purpose was to demonstrate consistent participants' immune respondents to receiving 3 separate lots of V920 through 28 days postvaccination. In addition to the 3 lot groups, a high-dose group and a placebo group were studied. A native of all treat groups' representative groups continued through 24 months postvaccination in the extension study to evaluate long-term safety. The primary hypothesis states that the geometric mean titer of the anti-Zaire ebolavirus (ZEBOV) glycoprotein antibody at 28 days postvaccination is equivalent across the three consistency lots.

    Clinical Trial NCT03031912  Phase 2: African-Canadian Study of HIV-Infected Adults and a Vaccine for Ebola - ACHIV-Ebola 

    • This Phase 2 study s a randomized, placebo-controlled, multi-site, double-blind trial of V920 (rVSVΔG-ZEBOV-GP) Ebola Virus vaccine candidate in subjects with HIV infection to be conducted in conformance with Good Clinical Practices. The study will take place at 2 Canadian sites (Centre Hospitalier de l'Université de Montréal and Ottawa General Hospital) and 2 African sites (Centre MURAZ, Burkina Faso, and Centre Hospitalier National Aristide Le Dantec, Dakar, Senegal). 

    Clinical Trial NCT02314923: Placebo-Controlled, Dose-Response, Safety and Immunogenicity Study of Vesicular Stomatitis Virus (VSV) Ebola Vaccine in Healthy Adults (V920-004)

    • This is a Phase 1 safety and tolerability study to evaluate a novel vaccine to Ebola using a live replicating vesicular stomatitis virus (VSV) replacing the gene encoding the G envelope glycoprotein with the gene encoding the envelope glycoprotein from the Zaire strain of Ebola (VSVΔG-ZEBOV also known as BPSC-1001).