Ervebo

Ervebo. It is a vaccine used for the prevention of Ebola virus disease caused by the Zaire ebolavirus species. Developed by Merck & Co., it is a recombinant vesicular stomatitis virus–based vaccine expressing the glycoprotein of the Kikwit 1995 Ebola virus strain. The World Health Organization prequalified the vaccine in 2019, a critical step for its use in outbreak response, particularly in regions like the Democratic Republic of the Congo.

Medical uses

Ervebo is indicated for active immunization to prevent disease caused by Zaire ebolavirus in individuals 12 months of age and older. Its primary use is in ring vaccination strategies during Ebola virus disease outbreaks, as implemented by organizations like the World Health Organization and ministries of health in affected countries. Clinical trials, including the pivotal PREVAIL trial in Liberia and the STRIVE trial in Sierra Leone, demonstrated high vaccine efficacy in preventing infection. It is not approved for protection against other Ebolavirus species, such as Sudan ebolavirus or Bundibugyo ebolavirus.

Adverse effects

Common adverse reactions are generally mild to moderate and include injection site pain, headache, fever, muscle pain, and fatigue. These reactions are consistent with those observed with many other vaccines and typically resolve within a few days. Clinical studies conducted during the 2014-2016 Ebola virus epidemic in West Africa and subsequent use in the Kivu Ebola epidemic showed a favorable safety profile. As with any biological product, there is a remote possibility of more severe reactions, including anaphylaxis, necessitating appropriate medical supervision during administration.

Pharmacology

Ervebo is a live, attenuated vaccine based on a genetically engineered vesicular stomatitis virus (VSV) where the native VSV glycoprotein gene is replaced with the gene encoding the glycoprotein of Zaire ebolavirus. This recombinant VSV-ZEBOV construct cannot cause Ebola virus disease but triggers a robust immune response against the Ebola virus glycoprotein. The vaccine induces both humoral immunity, producing neutralizing antibodies, and cell-mediated immunity. Pharmacokinetic data are not typically required for vaccines, as their mechanism is immunological rather than metabolic.

History

The vaccine's development originated from work at the Public Health Agency of Canada's National Microbiology Laboratory in Winnipeg. Following promising preclinical studies, the vaccine candidate was licensed to NewLink Genetics and subsequently to Merck & Co. for large-scale development. Its first major field use was during the 2014-2016 Ebola virus epidemic in West Africa, where it was deployed in clinical trials like Ebola ça Suffit in Guinea. In 2019, it received approval from the European Medicines Agency and prequalification from the World Health Organization, followed by approval from the U.S. Food and Drug Administration.

Society and culture

The deployment of Ervebo has been a significant milestone in global public health, particularly for epidemic preparedness in low-income countries. Its use in complex emergencies, such as the outbreaks in the Democratic Republic of the Congo, involved coordination between Gavi, the Vaccine Alliance, UNICEF, and the World Health Organization. The vaccine's development and stockpiling raise important discussions about equitable access to medical countermeasures and the challenges of conducting clinical research during humanitarian crises. It is listed on the World Health Organization Essential Medicines List. Category:Vaccines Category:World Health Organization essential medicines