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Brief Summary

The goal of this clinical trial is to learn if ChAdOx1 RVF, a candidate vaccine against RVF, provides an adequate immune response and determine its safety among Kenyan adults. The main aims are:

To assess the proportion of individuals mounting an immune response following vaccination with a single dose of ChAdOx1 RVF
To monitor occurrence of any adverse events following vaccination
To assess whether two doses of ChAdOx1 RVF elicit an immune response that is more durable than that generated by a single dose of ChAdOx1 RVF Researchers will compare ChAdOx1 RVF vaccine to a rabies vaccine in 240 participants. Participants will be randomly allocated to one of three study groups and vaccinated with ChAdOx1 RVF or a control Rabies vaccine as follows. Group 1, composed of 120 participants, will receive a single dose of ChAdOx1 RVF vaccine at baseline and a single dose of rabies vaccine 3 months later. Group 2, composed of 60 adults, will receive two doses of ChAdOx1 RVF; the first dose at baseline and the second dose 3 months later. Group 3, composed of 60 adults, will receive two doses of rabies vaccine; the first dose at baseline and the second dose 3 months later. Participants will receive daily phone calls after each vaccination for the following six days to gather information on any symptoms they may experience. Participants will be instructed to contact the study team at any time should they experience any clinical symptoms. Blood samples will be collected at baseline (before vaccination) and at scheduled follow-up visits (8 visits over the duration of the study, i.e. days 7, 14, 28, 84, 91, 112, 365 and 540 after the first vaccination) for monitoring of immune responses. Up to 20mls of blood will be collected at each scheduled visit. Participants will be followed-up for 18 months from the first dose of vaccine. Adverse events following vaccination will be monitored throughout the study and reviewed by an independent Data and Safety Monitoring Board (DSMB)

Outcome Measures

Primary Outcomes (1)

To assess the rate of seroconversion for RVFV neutralizing antibodies 28 days post-vaccination with a single dose of ChAdOx1 RVF
The proportion of vaccinees in each study group mounting neutralizing antibodies against live RVFV (i.e., seroconversion, as measured by FRNT80
28 days post-vaccination with one dose of ChAdOx1 RVF

Secondary Outcomes (9)

Geometric Mean Antibody Titre for neutralizing antibody titres (GMT) measured by FRNT80
Days 0, 7, 14, 28, 84, 112, 365 and at 18 months
Geometric mean antibody titre as measured by FRNT80 for IgG antibody titres
Days 0, 7, 14, 28, 84, 112, 365 and at 18 months
Spot Forming Units per 1,000,000 PBMCs (SFU/10⁶ PBMCs) for IFN-γ responses to RVFV Gn and Gc glycoproteins measured by enzyme-linked immunospot (ELISpot) assay
Days 0, 7, 14, 28, 84, 112, 365 and at 18 months
T-cells/10^6 PBMCs for multi-functional T cell responses to RVFV Gn and Gc glycoproteins as measured by flow cytometry.
Days 0, 7, 14, 28, 84, 112, 365 and at 18 months.
Number of Participants With Serious Adverse Events
Throughout the study, upto 24 months.
+4 more secondary outcomes

Other Outcomes (3)

To assess if anti-ChAdOx1 vector immunity influences response to ChAdOx1 RVF vaccination
Day 0 and 84
To estimate exposure to natural RVFV infection in the trial population
Days 0, 28, 84, 112, 365 and at 18 months
To assess whether sera from ChAdOx1 RVF vaccinees can passively protect animals from RVFV challenge
Sera collected at day 28 post-vaccination

Study Arms (3)

Single dose ChAdOx1 RVF

EXPERIMENTAL

Group 1, composed of 120 participants, will receive a single dose of ChAdOx1 RVF vaccine at baseline and a single dose of rabies vaccine 3 months later

Biological: ChAdOx1 RVFBiological: Rabies Vaccine

Double dose ChAdOx1 RVF

EXPERIMENTAL

Group 2, composed of 60 adults, will receive two doses of ChAdOx1 RVF; the first dose at baseline and the second dose 3 months later.

Biological: ChAdOx1 RVF

Rabies vaccine

ACTIVE COMPARATOR

Eligibility Criteria

Age18 Years - 50 Years

Sexall

Healthy VolunteersYes

Age GroupsAdult (18-64)

You may qualify if:

Healthy adult aged 18-50 years
For females only, willingness to practice continuous effective contraception up to one month following the second vaccination (i.e. duration of 4 months starting from enrolment) and a negative pregnancy test on the day(s) of screening. Effective contraception is defined as a contraceptive method with failure rate of less than 1% per year when used consistently and correctly, in accordance with the product label. Examples of these include combined oral contraceptives, injectable progestogen, implants of etenogestrel or levonorgestrel, intrauterine device. Female participants will be asked for written confirmation of any family planning methods used by provision of health records. These records will be reviewed and counselling for adherence done at each study visit as per the protocol schedule of attendances. Participants who do not have adequate methods of contraception will be referred to their local dispensary where this will be dispensed for free or to Kilifi County Hospital (KCH). Costs incurred for obtaining contraception at KCH will be covered by the study.

MeSH Terms

Conditions

Rift Valley Fever

Interventions

Rabies Vaccines

Condition Hierarchy (Ancestors)

Hepatitis, Viral, AnimalHepatitis, AnimalInfectionsMosquito-Borne DiseasesVector Borne DiseasesArbovirus InfectionsVirus DiseasesBunyaviridae InfectionsRNA Virus InfectionsHemorrhagic Fevers, ViralHepatitisLiver Diseases

Study Design

Study Type

interventional

Phase

phase 2

Allocation

RANDOMIZED

Masking

TRIPLE

Who Masked

PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR

Masking Details

Investigators and participants will be blinded to the allocations. Only the pharmacist and the nurse administering the vaccine will be unblinded. The allocation will be to one of the three treatment arms per a computer-generated randomization schedule.

Purpose

PREVENTION

Intervention Model

PARALLEL

Model Details: Randomized, controlled, double-blinded phase 2 trial

Sponsor Type

OTHER

Responsible Party

SPONSOR

Safety and Immunogenicity of a Candidate Rift Valley Fever Vaccine (RVF003)

Brief Summary

Registry Overview

Trial Relationships

Study Timeline

First Submitted

First Posted

Study Start

Primary Completion

Study Completion

Conditions

Outcome Measures

Primary Outcomes (1)

Secondary Outcomes (9)

Other Outcomes (3)

Study Arms (3)

Single dose ChAdOx1 RVF

Double dose ChAdOx1 RVF

Rabies vaccine

Interventions

Eligibility Criteria

You may qualify if:

Sponsors & Collaborators

Study Sites (1)

MeSH Terms

Conditions

Interventions

Condition Hierarchy (Ancestors)

Enrollment

Study Design

Study Record Dates

You may not qualify if:

Intervention Hierarchy (Ancestors)

Data Sharing

Source record

Locations

Safety and Immunogenicity of a Candidate Rift Valley Fever Vaccine (RVF003)

Brief Summary

Registry Overview

Trial Relationships

Related Scientific Literature

Study Timeline

First Submitted

First Posted

Study Start

Primary Completion

Study Completion

Conditions

Outcome Measures

Primary Outcomes (1)

Secondary Outcomes (9)

Other Outcomes (3)

Study Arms (3)

Single dose ChAdOx1 RVF

Double dose ChAdOx1 RVF

Rabies vaccine

Interventions

Eligibility Criteria

You may qualify if:

Sponsors & Collaborators

Study Sites (1)

MeSH Terms

Conditions

Interventions

Condition Hierarchy (Ancestors)

Enrollment

Study Design

Study Record Dates

You may not qualify if:

Intervention Hierarchy (Ancestors)

Data Sharing

Source record

Locations