By Stan Deresinski, MD, FACP, FIDSA, FESCMID

Clinical Professor of Medicine, Stanford University

Dr. Deresinski reports no financial relationships relevant to this field of study.

SYNOPSIS: In a scientific/public health triumph, the first vaccine for the prevention of Ebola virus infection has been approved. If administered prior to 10 days after exposure, its protective efficacy is 100%.

SOURCE: U.S. Food & Drug Administration. First FDA-approved vaccine for the prevention of Ebola virus disease, marking a critical milestone in public health preparedness and response. Dec. 19, 2019. Available at: Accessed Jan. 10, 2020.

On Dec. 19, 2019, the U.S. Food and Drug Administration (FDA) announced the approval of the first FDA-approved vaccine (rVSV-ZEBOV, Ervebo), for the prevention of Ebola virus disease (EVD) in individuals 18 years of age and older. In 2018, the World Health Organization began using Ervebo while it was still considered investigational and was provided under an expanded access program in attempts to deal with the ongoing outbreak in the Democratic Republic of the Congo. Ervebo, which is administered as a single injection, is a live attenuated vesicular stomatitis virus vaccine engineered to present an Ebola envelope glycoprotein.

Previously, Ervebo had demonstrated efficacy in a trial in Guinea in a clustered (ring) study that randomized contacts of cases as well as contacts of contacts to receive immediate vaccination or vaccination delayed for 21 days. The vaccine had 100% efficacy in preventing Ebola cases occurring with onset more than 10 days after its administration. While no Ebola cases occurred then among the 2,108 subjects with immediate vaccination, 10 cases occurred in the 1,429 subjects whose vaccination was delayed. The vaccine is well tolerated, although 70% of recipients reported injection site pain, while 37% and 34% complained of headache and feverishness, respectively.

Several other vaccines remain in clinical trials. In the meantime, the manufacturer (Merck) has a stockpile of 190,000 doses and has plans to make another 650,000 doses available over the next 18 months.