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.
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 approval 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 in the DRC. This is the first and only vaccine currently licensed by the US Food and Drug Administration to prevent EVD. This report, published by the CDC on January 8, 2021, summarizes the Advisory Committee on Immunization Practices' recommendations for using the rVSVΔG-ZEBOV-GP Ebola vaccine (Ervebo) in the USA.
Zabdeno and Mvabea Ebola vaccine therapy is a prime-boost vaccination approach for preventing infectious diseases. 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.
Ebola Antiviral Therapeutics
Treatments are being developed to treat EVD work by stopping the virus from making copies of itself, says the CDC. And on October 14, 2020, the FDA announced its approval of Inmazeb (atoltivimab, maftivimab, and odesivimab-ebgn), a mixture of (3) monoclonal antibodies for the treatment for Zaire ebolavirus (Ebola virus) infection in adult and pediatric patients.
During the 2018 eastern DRC outbreak, 4 investigational treatments were initially available to treat EVD patients. Two of those drugs called Regeneron (REGN-EB3) and mAb114, the overall survival rate was much higher. These 2 antiviral drugs currently remain in use in the DRC.
On April 17, 2020, the FDA accepted for Priority Review a new Biologics License Application for REGN-EB3, an investigational triple antibody cocktail treatment for EVD. Previously, REGN-EB3 received Orphan Drug and Breakthrough Therapy designation from the FDA.
On June 18, 2020, a study 'Recent successes in therapeutics for Ebola virus disease: no time for complacency' was published in The Lancet. 'Although the overall reduction to a residual 34–35% CFR with the most effective mAb-based therapeutics represents a remarkable step forward, the PALM results suggest substantial room to improve outcomes in the acute Ebola virus disease.'
On July 30, 2020, the Biomedical Advanced Research and Development Authority announced it entered an agreement to procure REGN-EB3 as part of the US government’s goal of building national preparedness for public health emergencies.
On December 22, 2020, Ridgeback Biotherapeutics LP confirmed that the U.S. Food and Drug Administration (“FDA”) approved Ebanga to treat Ebola. Ebanga is now approved to treat infections caused by Zaire ebolavirus in adult and pediatric patients.
Ebola Outbreak News
While Ebola cases are sporadic in the USA, and those that have occurred have been the result of infections acquired by individuals in other countries, says the U.S. FDA.
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 stockpile 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 being funded through a US$ 20 million contribution from the United States Agency for International Development, committed in 2017 and specifically dedicated to supporting a stockpile of licensed Ebola vaccines to help tackle future outbreaks of this disease.
January 12, 2021 - The four leading international health and humanitarian organizations announced today establishing a global Ebola vaccine stockpile to ensure outbreak response. The stockpile will allow countries, with the support of humanitarian organizations, to contain future Ebola epidemics by ensuring 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 licensed 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 outbreak 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 outbreaks 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.
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 take place 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?
June 26, 2020 - 10th Ebola Outbreak Ends as the 11th Ramps Up.
March 22, 2020 - Ebola Vaccination Recommended For At-Risk Healthcare Staff.
Ebola Vaccine 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 diseases. 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.