The vaccine rVSVΔG-ZEBOV-GP (Ervebo) not only reduces the risk for Ebola infection but also halves mortality rates. This is the result of a study published in The Lancet Infectious Disease.
Rebecca Coulborn, an epidemiologist at Epicentre in Paris, France, and colleagues analyzed data collected during the 10th Ebola epidemic in the Democratic Republic of the Congo. Their analysis revealed that among the 2279 patients with confirmed Ebola who were admitted to an Ebola health facility between July 27, 2018, and April 27, 2020, the mortality risk was 56% for unvaccinated patients. In vaccinated patients, however, it was only 25%. The reduced mortality applied to all patients, regardless of age and gender.
The study was funded by Doctors Without Borders. For data collection, Epicentre, the epidemiological division of Doctors Without Borders, collaborated with the Institut National de Recherche Biomédicale and the Ministry of Health of the Democratic Republic of the Congo.
The study authors focused on the Ervebo vaccine, which is approved for use against Zaire ebolavirus in the European Union, the United States, and some African countries, among others. It is the only Ebola vaccine currently recommended for use during an epidemic. Ervebo is administered intramuscularly as a single dose and is approved for adults aged 18 years and older.
The vaccine is primarily recommended for ring vaccination of individuals at a high risk for infection during an epidemic. In vaccine studies, the vaccine has been used for ring vaccinations among contacts of diagnosed cases since the end of the Ebola outbreak in West Africa in 2014 and 2015 and since 2018 in the Democratic Republic of the Congo.
The preliminary estimated vaccine effectiveness 10 days after vaccination is 97.5%-100%. The duration of protection is unknown. Individuals who became ill despite vaccination typically experienced a milder course of illness.
Although people should be vaccinated as early as possible during Ebola outbreaks, the results of the Epicentre study showed that the vaccine still protects against the risk for infection even when administered after exposure to the virus.
Furthermore, Coulborn and her team found no antagonistic effect between vaccination and Ebola treatment in their analysis. "Vaccination following exposure to a person infected with Ebola still provides significant protection against death, even if administered shortly before the onset of symptoms," said study author Coulborn in a press release from Doctors Without Borders.
This story was translated from the Medscape German edition using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.