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ERVEBO (rVSVΔG-ZEBOV-GP) Ebola Vaccine

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May 12, 2022
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Ervebo (rVSVΔG-ZEBOV-GP) Ebola Vaccine Description 2022

Merck's Ervebo, Ebola Vaccine (rVSV-ZEBOV-GP) (v920) is a live, recombinant, replication-competent vaccine. Ervebo's active ingredient is Vesicular Stomatitis Virus (VSV), in which its surface protein has been replaced with that of Zaire ebola virus disease (EBOV). In addition, it was genetically engineered to express the main glycoprotein from the Zaire ebolavirus to provoke a neutralizing immune response to the Ebolavirus. This Ebola vaccine's inactive ingredients include recombinant human serum albumin, and tromethamine (Tris) buffer, which contains a trace amount of rice protein.

Ervebo (rVSV-ZEBOV) is the first Ebola vaccine licensed by the U.S. Food and Drug Administration (FDA) to prevent EVD in individuals 18 years of age and older in December 2019. 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. Merck Sharp & Dohme B.V.'s vaccine was authorized for use in Canada, and the European Union by the European Medicines Agency on November 11, 2021 - (EMEA/H/C/004554) and by the World Health Organization (WHO).

It is not possible to become infected with EBOV from the vaccine because the vaccine only contains a gene from the Ebola virus, not the whole virus. Specifically, it contains a gene for the EBOV glycoprotein that replaces the gene for the native VSV glycoprotein, says the U.S. CDC.

Since the Ervebo vaccination program in central Africa in 2019, approximately 300,000 persons have been vaccinated with the ERVEBO vaccine. The Ervebo vaccine protects people from Zaire Ebolavirus, but not against other species of Ebolavirus or Marburgvirus. People cannot get EVD from the Ervebo vaccine.

As of March 8, 2022, the U.S. CDC stated 'The correlate of protection, or the specific immune response to the ERVEBO vaccine that closely relates to protection against infection with EBOV, is unknown and still being studied. Whether it is effective when administered concurrently with antiviral medication, immune globulin, and/or blood or plasma transfusion is also unknown. And the duration of protection conferred by an initial dose of ERVEBO is also unknown. Furthermore, a booster dose for people who have been previously vaccinated may extend the duration of protection for ERVEBO. Scientists continue to monitor people who have received the vaccine to learn more.'

ERVEBO does not provide protection against other species of Ebolavirus or Marburgvirus. Drugbank's Accession Number: DB15595. ATC code: J07BX02. STN: 125690. Clinical Reviewer: Rebecca Reindel.

New Jersey-based 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 initially developed the vaccine, retained noncommercial rights in the agreement.

Ervebo (rVSVΔG-ZEBOV-GP) Ebola Vaccine History

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. On December 19, 2019, the FDA announced the licensing of the Ervebo (rVSVΔG-ZEBOV-GP) Ebola Vaccine. 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.

On January 8, 2021, the U.S. CDC's Advisory Committee on Immunization Practices (ACIP) recommended the use of the rVSVΔG-ZEBOV-GP Ebola vaccine (Ervebo) in the U.S. for preexposure vaccination for adults aged ≥18 years 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.

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. In addition, the injectable single-dose Ebola vaccine Ervebo (rVSV∆G-ZEBOV-GP, live) was included.

Ebola cases are sporadic in the U.S. They 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.

Ervebo (rVSVΔG-ZEBOV-GP) 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. However, the duration of protection conferred by Ervebo is unknown. In addition, when administered concurrently with antiviral medication, the vaccine's effectiveness, immune globulin (IG), and/or blood or plasma transfusions are unknown.

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

The WHO published the revised Ebola Vaccine FAQ, and the U.S. CDC published 'Ebola Vaccine: Information for U.S. Healthcare Providers.'

Ervebo (rVSVΔG-ZEBOV-GP) 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 confirmed EVD patients and 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 ten days were selected to account for the incubation period of EVD and the unknown length of time from vaccination to protective immunity development.

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. However, Merck says, 'do not administer Ervebo to individuals with a severe allergic reaction (e.g., anaphylaxis) to any vaccine component, including rice protein.' This is because 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. Therefore, 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.

Ervebo (rVSVΔG-ZEBOV-GP) Ebola Vaccine Side Effects

Injection-site side events include injection-site pain, swelling, and redness. The most common injection-site adverse events were injection-site pain (70%), swelling (17%), and redness(12%). The most common systemic adverse events reported following vaccination with ERVEBO were headache (37%), feverishness (34%), muscle pain (33%), fatigue (19%), joint pain (18%), nausea (8%), arthritis (5%), rash (4%) and abnormal sweating (3%). 

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).

Tell your health care provider promptly about any unusual or severe symptoms after receiving this vaccine. You may also report any side effects to Merck Sharp & Dohme Corp, a Merck & Co., Inc. subsidiary, at 1-877-888-4231 or directly to Vaccine Adverse Event Reporting System (VAERS). The VAERS toll-free number is 1-800-822-7967, or report online to www.vaers.hhs.gov.

International Coordinating Group on Vaccine Provision - Ebola Vaccine (rVSVΔG-ZEBOV-GP) 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. 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.

Ervebo (rVSVΔG-ZEBOV-GP) Ebola Vaccine U.S. CDC Presentations

On November 3, 2021, Jason Malenfant, MD, MPH, Epidemic Intelligence Service Officer Viral Special Pathogens Branch CDC, presented 'Evidence for Expansion of Recommendations for PreExposure Vaccination with rVSVΔG-ZEBOV-GP Ebola Vaccine for Special Pathogens Treatment Centers and Laboratory Response Network Facilities.' In addition, Wilbur Chen, MD, University of Maryland School of Medicine Chair, Ebola Vaccine Working Group, presented an Overview. And Caitlin Cossaboom, DVM, Ph.D., MPH, presented Policy Questions.

    Ervebo (rVSVΔG-ZEBOV-GP) Ebola Vaccine News 2015 - 2022

    May 10, 2022 - The UK's FCDO advises against all but essential travel to the province of Equateur in the DRC due to the ongoing outbreak of Zaire Ebola.

    May 5, 2022 - The WHO African Region reported that 353 people were vaccinated in Mbandaka, the DRC.

    April 27, 2022 - The DRC launched an Ebola vaccination in Mbandaka to halt the spread of the virus following an outbreak that has claimed two lives since 21 April. Around 200 doses of the rVSV-ZEBOV Ebola vaccine will be deployed.

    April 24, 2022 - The Africa Pathogen Genomics Initiative - Africa CDC confirmed the recent case in the DRC was vaccinated against the Ebola virus in 2020 and is not known to be an EVD survivor. 

    April 23, 2022 - The WHO Africa Region confirmed the DRC has stockpiles of the rVSV-ZEBOV Ebola vaccine available in Goma and Kinshasa, which will be sent to Mbandaka and administered through the ‘ring vaccination strategy.

    February 9, 2022 - A new study by Liu et al. reports frequent Ebola virus persistence in the brain ventricular system of primates that survived acute disease after monoclonal antibody-based treatment. Viral persistence was associated with lethal recrudescence of Ebola, including severe inflammation in the brain. These findings have implications for long-term follow-up efforts to reduce individual disease relapse/recrudescence of viral persistence in survivors of EBOV infection.

    February 8, 2022 - A new study published by PNAS examined the antibody response at 21 days and six months postvaccination after a single dose of rVSVΔG-ZEBOV-GP among EVD-exposed and potentially exposed populations in the DRC. At 21 d of follow-up, 87.2% had an antibody response. Additionally, 95.6% demonstrated antibody persistence at six mo of follow-up. These findings give crucial evidence that antibody response and persistence after Ebola vaccination are robust in outbreak settings in the DRC.

    December 16, 2021 - The WGO reported the Ebola outbreak that erupted in the DRC’s North Kivu Province in October – the second in 2021 – was today declared over. In total, 11 cases (eight confirmed, three probable), including six deaths, were reported. More than 1800 people were vaccinated. The outbreak marks the first time the recently-licensed ERVEBO vaccine against Ebola was used in the DRC.

    November 20, 2021 - The ECDC reported since the last report, no new EVD cases nor deaths have been reported in North Kivu province in the eastern region of the DRC. This Health Area is about 50km from Butembo city, where the DRC¶s 12th EVD outbreak occurred in 2021, lasting for around three months until it was declared over on 3 May 2021. In total, eight confirmed and three probable EVD cases, including nine deaths (six among the confirmed cases), were reported by WHO since the start of the outbreak on October 8, 2021, with the last confirmed case reported on October 30, 2021.

    November 8, 2021 - The WHO Africa reported the overall case fatality rate of the current Ebola outbreak in the DRC is 81.8% (9/11) and 75.0% (6/8) among confirmed cases. And a total of 485 persons have been vaccinated against EVD from the inception of the vaccination activities.

    November 4, 2021 - The U.S. CDC issued a Level 3 Travel Advisory that stated: Travelers should avoid all nonessential travel to Beni Health Zone in North Kivu Province of the Democratic Republic of the Congo.

    November 3, 2021 - The U.S. CDC's vaccine advisory committee vote supported the use of vaccines as PrEP for certain health care personnel and/or lab support staff at facilities that handle Ebola virus specimens.

    November 2, 2021 - Additional cases and deaths were confirmed by the WHO in the Ebola virus disease outbreak in the DRC, with two new health areas affected. As of 30 October 2021, the Beni Health Zone reported 198 new alerts, including nine deaths. An additional 445 alerts, including 21 deaths, were notified from seven other HZs. A total of 394 people (67 primary care providers, including nine high-risk contacts, nine contacts of contacts, and 49 probable contacts) have been vaccinated, including 182 contacts of contacts, 125 probable contacts, and 87 high-risk contacts.

    November 1, 2021 - The ECDC confirmed eight EVD cases, including six deaths, since the start of the current outbreak (8 October 2021). In total, 551 contacts were followed up.

    October 24, 2021 - The WHO Africa Tweeted the 3rd fatality, sixth case, and has been confirmed in the DRC's latest Ebola outbreak

    October 19, 2021 - The ECDC reported three people died, and all cases were from a DRC community in the Beni health zone. Ten patients are hospitalized, including two confirmed and eight suspected cases, and 386 contacts have been established so far, with 322 followed in the last 24 hours, and 140 people have been vaccinated so far. The index case, diagnosed on 8 October and deceased in a health facility, had three family members who died in September, but they were not investigated for Ebola. The detected Ebola strain is 96% similar to the 10th EVD outbreak in the Democratic Republic of the Congo (2018-2020).

    October 13, 2021 - The WHO confirmed a vaccination program had launched in the DRC related to the new Ebola outbreak. About 1,000 doses of the rVSV-ZEBOV Ebola vaccine and other medical supplies were delivered from the capital city of Kinshasa to Goma city in North Kivu. In addition, around 200 doses were sent to Beni city near the Butsili health area, where the confirmed case was detected. In addition, vaccinators are using the "ring vaccination" approach, where contacts and contacts of contacts are vaccinated. And the DRC has more than 12,000 vaccine doses in Kinshasa that can be deployed if necessary.

    October 11, 2021 - The CEO of GAVI Tweeted 'about 1,000 doses of the rVSV-ZEBOV vaccine are still available in the country (DRC), so vaccination can start immediately to contain this outbreak. And 248,500 supported doses are available in the global stockpile ready to ship in case of need' @GaviSeth.

    October 10, 2021 - The WHO confirmed the recent case was a 3-year-old male who developed physical weakness, loss of appetite, abdominal pain, breathing difficulty, dark stool, and blood in their vomit. And died on October 6th. This case follows a cluster of three deaths (two children and their father) who were the boy's neighbors. These three patients died on 14, 19, and 29 September 2021 after developing symptoms consistent with Ebola; however, none were tested for the virus. No vaccination plan was announced for the 'close-contacts.'

    October 8, 2021 - A case of Ebola has been confirmed in the DRC. The report from the biomedical lab, the INRB, said the positive result came from a 2-year-old in a densely populated neighborhood of the city of BeniDRC's of the epicenters of the 2018-20 Ebola outbreak. The DRC's health minister declined to confirm the information.

    August 17, 2021 - The WHO Africa confirmed the vaccine deployment from Guinea used 2,000 doses from Merck that are being used under the "ring strategy" where people who have come into contact with a confirmed Ebola patient are given the vaccine as first responders and health workers.

    August 17, 2021 - The EMA published updated Procedural steps are taken and scientific information after the Ervebo authorization.

    August 9, 2021 - The WHO reported, 'Guinea has previous experience managing recurring viral hemorrhagic diseases such as EVD and Lassa fever, but reported first time that Marburg Virus Disease has been reported.'

    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 and virus replication and propagation disease.

    June 19, 2021 - ThereportedGuinea'sea's 16 confirmed and seven probable cases reportedGuinea'sea's latest Ebola outbreak, in which 11 patients survived, and 12 lives were 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 patients 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 had 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, six 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 four months.

    March 25, 2021 - UNICEF confirmed 4,345 people had been vaccinated, including 1,801 frontline staff, since the Ebvaccination'son's official launch in Guinea on February 23, 2021.

    February 25, 2021 - 'As Ebola immunization scales up in Guinea'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 patients, including five deaths, have been reported in Guinea.

    February 12, 2021 - Media reports indicate the DRC confirmed a third Ebola case in North Kivu. Provincial health minister Eugene Nzanzu Salita said, "We are in a meeting to gather information. The recent outbreak would be the DRC's 12th.

    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 a recent Ebola case 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.

    January 27, 2021 - The journal Nature published a new study: Ebola virus antibody decay–stimulation in a high proportion of survivors. The most increased 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.

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

    September 30, 2020 - The U.S. CDC issued an Alert - Level 2, centAfrica'sca'sd Precautions, for prospective visitors to centAfrica'sca'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 WHO 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 vesiMerck'sck'stitis virus (rVSV) technology that is the basis of Merck'sck's Ebola Zaire virus vaccine, ERVEBO, the first rVSV vaccine approved for use in humans.

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

    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. FDA 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. 

    May 23, 2019The Ethics Committee of the School of Public Health of the University of Kinshasa approved the compassionate belt vaccination protocol amendment 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

    Merck Announces FDA Approval for ERVEBO® (Ebola Zaire Vaccine, Live). Clinical trial information is available at Merck Vaccines.