Vaccine Info

Ervebo Ebola Vaccine

Authored by
Last reviewed
July 8, 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. 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. In addition, this vaccine contains a trace amount of rice protein.

Ervebo is the first Ebola vaccine currently licensed by the U.S. Food and Drug Administration to prevent Ebola virus disease.

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 USA, or work as laboratorians or other staff at biosafety level 4 facilities in the USA.

The U.S. FDA granted a 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. With the support of humanitarian organizations, the supply will allow countries 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. On February 15, 2020, Merck announced that 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. In addition, 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 resulted from 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. For example, 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. However, 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. However, 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. Therefore, 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.

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. In addition, 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 with seniors 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 Stockpile

The ICG manages the Ebola vaccine's global stockpile, created as an additional tool to help control Ebola outbreaks. Ebola outbreaks are relatively rare and unpredictable in nature. 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 January 12, 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 if 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

    July 6, 2021 - New York-based Mount Sinai researchers have uncovered the complex cellular mechanisms of the Ebola virus, which could help explain its severe toll on humans and identify potential pathways to treatment and prevention. In a study published in mBio, the team reported how a protein of the Ebola virus, VP24, interacts with the double-layered membrane of the cell nucleus, leading to significant damage to cells along with virus replication and the propagation of disease.

    June 19, 2021 - The WHO Africa reported 16 confirmed and seven probable cases reported in Guinea’s latest Ebola outbreak, in which 11 patients survived and 12 lives lost. The WHO delivered around 24,000 Ebola vaccine doses and supported the vaccination of nearly 11,000 people at high risk, including over 2,800 frontline workers. 

    May 3, 2021 - The WHO announced the end of the 12th Ebola outbreak in the Democratic Republic of the Congo, just three months after the first case was reported in North Kivu. The WHO vaccinate nearly 2,000 people at high risk, including over 500 frontline workers.

    April 9, 2021 - Two new confirmed Ebola cases and three probable cases, including three deaths, have been reported by the WHO in Guinea. All new cases are being reported from the Soulouta sub-prefecture in the region of N¶Zerekore. Ring vaccination around these new Ebola cases started as of April 2, 2021. A total of 129 contacts have been vaccinated.

    April 2, 2021 - The WHO Africa Tweeted 'Ring vaccination site set up in Soulouta village, Guinea, one day after a new Ebola case was reported. About 129 contacts linked to the recent case have been vaccinated.

    April 1, 2021 - During the 2018–2020 Ebola virus disease (EVD) outbreak in North Kivu province in the Democratic Republic of Congo, EVD was diagnosed in a patient who had received the recombinant vesicular stomatitis virus-based vaccine expressing a ZEBOV glycoprotein (rVSV-ZEBOV) (Merck). His treatment included an Ebola virus (EBOV)–specific monoclonal antibody (mAb114), and he recovered within 14 days. However, 6 months later, he presented with severe EVD-like illness and EBOV viremia, and he died. We initiated epidemiologic and genomic investigations that showed that the patient had had a relapse of acute EVD, leading to a transmission chain resulting in 91 cases across six health zones over 4 months.

    March 25, 2021 - UNICEF confirmed 4,345 people had been inoculated (including 1,801 frontline staff) since the Ebola vaccination's official launch in Guinea on February 23, 2021.

    March 16, 2021 -  Cumulatively, 30 EVD cases, 15 deaths (CFR: 50%), and eight recoveries have been reported from DR Congo (12 cases; 6 deaths; 2 recoveries) and Guinea (18; 9; 6). Seven healthcare workers are amongst the confirmed cases: DR Congo (2) and Guinea (5).

    March 5, 2021 - The UN News reported more than 1,600 people had received Ebola virus vaccinations in Guinea. “We are using the ring vaccination,” said Dr. Ibrahima Socé Fall, the Assistant Director-General of WHO responsible for emergency response, referring to the strategy that inhibits the spread of disease by vaccinating only those most likely to be infected. “We are vaccinating the contacts of cases, the contact of contacts, and their contacts. With this strategy, we can control this type of outbreak. But we are going to need more vaccines,” Dr. Fall told journalists in Geneva.

    February 25, 2021 - The WHO reported, 'As Ebola immunization scales up in Guinea, the country’s neighboring nations are on high alert, urgently preparing to detect, isolate and manage any cases and quickly stamp out potential cross-border outbreaks.  Nine cases, including five deaths, have been reported in Guinea. While no confirmed Ebola cases have been recorded outside of the country, the latest outbreak in N’Zerekore prefecture is close to porous borders with Liberia, Sierra Leone, and Côte d'Ivoire. In the Democratic Republic of Congo’s North Kivu province, there have been eight confirmed cases of Ebola and four deaths in the latest outbreak that was declared on 7 February. Persistent insecurity, tragically illustrated by the recent death of Italian Ambassador Luca Attanasio in the region, is hampering efforts to detect cases and trace the contacts of those infected. More than 650 people have been vaccinated so far. About 8,000 vaccine doses were still available in the country at the end of the 11th Ebola outbreak. Another 4,320 doses are expected to arrive early next week.'  

    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 - The BBC reported about 8,000 doses of the Ervebo vaccine 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 USA. 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 to rice protein should not receive Ervebo.

    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, 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 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 licensed doses and expects these doses to start becoming available in approximately the third quarter of 2020.

    December 19, 2019The U.S. Food and Drug Administration announced the approval of Ervebo, the first FDA-approved vaccine for preventing 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. In addition, 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.

    October 18, 2019 - The EMA’s human medicines committee 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.

    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 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 Trials