The rVSV-ZEBOV vaccine has demonstrated real-world effectiveness of approximately 84 per cent against Ebola virus disease, revealed a recent study carried out by researchers in Europe and the Democratic Republic of the Congo (DRC). This retrospective, test-negative study, which analysed 618 individuals during the 2018-2020 Ebola virus epidemic in the DRC, supports the prophylactic use of rVSV-ZEBOV for future outbreaks, says GlobalData.
Stephanie Kurdach, Infectious Disease Analyst at GlobalData states, “The recombinant vesicular stomatitis virus – Zaire Ebola virus (rVSV-ZEBOV) vaccine is marketed by Merck under the name Ervebo. It has been marketed in the US and EU since 2019 and in 2020 the DRC became one of the first African countries to register the vaccine, along with Burundi, Ghana, and Zambia. rVSV-ZEBOV will have the biggest impact in nations where the virus is endemic, such as the DRC.”
Ebola virus disease is caused by the species orthoebolavirus zairense, which is primarily found in sub-Saharan Africa. It is transmitted through the bodily fluids of a sick or deceased person. The symptoms of Ebola disease can progress from fever, aches, and fatigue to diarrhea, vomiting, and unexplained bleeding. If left untreated, Ebola disease can cause death.
“The 2018-2020 Ebola virus epidemic in the DRC was the largest recorded outbreak in the country, and the second-largest outbreak worldwide. Over 300,000 individuals were vaccinated during the outbreak under an Expanded Access program, making it a prime opportunity to evaluate the effectiveness of the vaccine in a real-world setting, which has been lacking until now,” adds Kurdach.
Vaccine effectiveness was estimated using odds ratio calculations, which determined that ≥10 days after vaccination, rVSV-ZEBOV was 80 per cent effective against Ebola virus in females, 86 per cent in males, 80 per cent in children <15 years of age, 83 per cent in adults ≥15 years of age, and overall, 84 per cent effective.
According to GlobalData, there are seven other competing drugs that are marketed for Ebolavirus infections worldwide, including vaccines and monoclonal antibodies. A small number of vaccines are also in late-stage development. The Sabin Vaccine Institute currently has one vaccine candidate in Phase III and one in Phase II development.
Kurdach concludes, “The results of this retrospective study are promising for the widespread use of rVSV-ZEBOV during future outbreaks, particularly in nations where the virus is endemic, and a vaccine is most needed. Further research focusing on rVSV-ZEBOV’s effectiveness against severe disease, and it’s use as post-exposure prophylaxis would also be beneficial for populations most at-risk during a future outbreak.”