REVIVE (Response to the Ebola Virus Vaccine)

Ebola virus (EBOV; also known as Zaire ebolavirus, family Filoviridae) is among the most virulent infectious agents known, producing sporadic outbreaks of severe and highly lethal hemorrhagic fever in humans and nonhuman primates (NHPs). The West African Ebola Virus Disease (EVD) Outbreak of 2013 to 2016, which predominantly affected Sierra Leone, Liberia, and Guinea, resulted in 28,601 confirmed cases and 11,308 fatalities.

Multiple reports in the literature of recurrent infections among EVD survivors now exist. Some of these recurrent infections have also resulted in transmission to close contacts of these survivors. In December 2019, the U.S. Food and Drug Administration approved the recombinant Vasicular Stomatitis Virus delta-G (rVSVDG) Zaire Ebolavirus (ZEBOV) Glycoprotein (GP) (rVSVDG-ZEBOV-GP) Ebola vaccine (ERVEBO®; Merck) for use in people 18 years and older. The current literature and data on EBOV antibody levels in survivors suggest that while the humoral immune response to EBOV after natural infections wanes over weeks to months, the response to a single dose of rVSVDG-ZEBOV-GP vaccine is stable over at least two years.

In this pilot study, the investigators hypothesize that vaccination of EVD survivors with rVSVDG-ZEBOV-GP will result in a non-inferior immune response compared to vaccination of non-exposed age- and sex-matched individuals. This study will be an open-label, case-control study of the safety and immunogenicity of the rVSVDG-ZEBOV-GP vaccine comparing EVD survivors and EBOV-naïve community members in Sierra Leone. A total of 40 participants will be recruited and divided 1:1 into EVD survivors (cases) and EBOV-naïve age- and sex-matched community members (controls). Following a two week screening period, participants will be followed for six months post-vaccination.

Subject Population

Twenty EVD survivors and twenty age and sex-matched controls with no clinical history or immunologic evidence of prior EBOV infection will be enrolled. All participants will be citizens of Sierra Leone. In accordance with the currently approved use of the rVSVDG-ZEBOV-GP vaccine in Sierra Leone, all participants will be 18 years or older and pregnant and lactating females will be excluded.

While there is currently an effort to vaccinate all healthcare workers in Sierra Leone, EVD survivors are excluded in the current vaccine roll-out. The investigators plan to recruit EVD survivors including healthcare workers thus enhancing access to the vaccine for this population. All participants will be of African descent. The investigators plan to enroll an equal number of males and females.