This study is a vaccine-related clinical trial which will be conducted by our study team at Kenema Government Hospital (KGH)'s Viral Hemorrhagic Fever Program in collaboration with Tulane University School of Medicine. This study is funded by Merck \& Co., the developers of ERVEBO®. This investigational medicinal product (IMP) was successful in Sierra Leone through the Sierra Leone Trial to Introduce a Vaccine against Ebola (STRIVE) working with the College of Medical and Allied Health Services (COMAHS) at the University of Sierra Leone. ERVEBO® was also successfully tested in Liberia and the Republic of Guinea. These successful trials led to the United States Food and Drug Administration (USFDA) approval of ERVEBO®, as well as approval for therapeutic use in the Democratic Republic of the Congo, Burundi, Ghana, and Zambia. This particular vaccination study will focus on the anamnestic response to the ERVEBO® vaccine, (full name - rVSVDG-ZEBOV-GP Ebola Virus Vaccine). The original clinical trials conducted excluded Ebola Virus Disease (EVD) survivors from participating. However, with ongoing research, there is evidence of waning immune response and even recurrent infections in EVD survivors.
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.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
40
It is an Ebola virus vaccine
Kenema Government Hospital
Kenema, Eastern Province, Sierra Leone
RECRUITINGAssess the immunogenicity and durability of rVSVDG-ZEBOV-GP among EVD survivors compared with unexposed age- and sex-matched controls at six months post-vaccination
Serum samples will be tested for the presence of anti-EBOV GP immunoglobulin G (IgG) and anti-EBOV Viral Protein 40 (VP40) IgG using ELISA plates produced by Zalgen Labs, LLC and run according to the manufacturer's instructions.
Time frame: 6 months
Assess the incidence of adverse events after vaccination with rVSVDG-ZEBOV-GP among EVD survivors compared with unexposed age- and sex-matched controls
The investigators will assess the following adverse events at all post-vaccination follow-up time points: arthralgia, diarrhea, fatigue, fever, headache, induration, injection site pain, muscle pain, myalgia, and vomiting. Follow up visits will occur on days 1, 3, 7, 14, 28, 90 and 180 post vaccination.
Time frame: 6 months
Assess the durability of neutralizing antibody titers after immunization with rVSVDG-ZEBOV-GP among EVD survivors compared with unexposed age- and sex-matched controls at six months post-vaccination
The investigators will use Pseudovirus Neutralization Assay that has been adapted from a previously described Lassa pseudovirus to produce Ebola pseudoviruses (EBOVpp). EBOVpp are capable of a single round of replication, when used to infect a human embryonic kidney cell line which is capable of fluorescence.
Time frame: 6 months
Determine Fc-mediated innate effector function profiles in EVD survivors compared to both naïve vaccinees and EVD survivors vaccinated with rVSVDG-ZEBOV-GP.
The investigators will use a bead-based multiplexed platform to measure Fc-mediated effector functional profiles and virus specific antibodies using an established EBOV systems serology platform including: (A) monocyte/macrophage phagocytosis and activation, (B) neutrophil phagocytosis and maturation, (C) Natural Killer (NK) cell activation, and (D) complement deposition.
Time frame: 6 months
Assess the phenotype, function, and durability of EBOV specific T-cell responses in natural immunity (EVD survivors) and response to vaccination with rVSVDG-ZEBOV-GP in EVD survivors and naïve vaccinees
EBOV specific T-cells will be characterized by: (A) EBOV protein stimulation and intracellular cytokine staining, (B) magnetic bead-based assays to assess function in supernatants from stimulated cells, and (C) Two-color Interferon-Gamma and Tumor Necrosis Factor-Alpha (TNFa) Enzyme Linked Immunosorbent Spot (ELISPOT).
Time frame: 6 months
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.