Characterization of Adaptive Immune Responses to Oropouche Virus (OROV) Infection (OROV-IMM)

November 2, 2026 updated by: Institut Pasteur

Oropouche virus (OROV), a re-emerging South American arbovirus causing dengue-like fever and occasional neurological complications, is expanding its circulation towards more densely populated areas in French Guiana, as evidenced by recent cases near Cayenne in 2026. While animal models indicate that B cell-mediated humoral immunity is critical for viral control, the human antibody response to OROV remains poorly characterized. Despite WHO-led international research efforts, there is currently no vaccine, antiviral treatment, or described human monoclonal antibody against OROV - a major gap that hinders therapeutic and vaccine development. Identifying human neutralizing monoclonal antibodies could offer a promising therapeutic option, particularly for vulnerable populations such as pregnant women.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The goal of this project is to characterize the adaptive immune response to OROV infection during the convalescent phase.

The study is based on three complementary populations: (1) 17 adults with confirmed past OROV infection (2020) who will be recontacted for follow-up sampling; (2) 50 adults recruited prospectively from a village with ∼80% seroprevalence, aiming to include at least 20 seropositive individuals for robust analysis of antigen-specific B and T cell responses; and (3) an exploratory cohort of 1 to 10 newly confirmed OROV cases identified during the study period in the Cayenne region, enrolled during the convalescent phase (≥1 month post-diagnosis) to complement the immunological analyses conducted in the first two populations.

A 20 ml blood sample is collected, along with data collection (mainly health data), at the time of enrollment.

The study involves: (1) confirming past OROV infection by detecting OROV-specific polyclonal antibodies in plasma; and (2) characterizing OROV-specific B and T cell responses. Key methodological steps include: isolation of OROV-specific B cells by flow cytometry followed by single-cell culture and stimulation to generate human monoclonal antibodies; screening of secreted mAbs against OROV antigens combined with VDJ sequencing to characterize immunoglobulin repertoires; and structural characterization of neutralizing mAbs using cryo-electron microscopy and nano-imaging to identify conserved epitopes.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
80

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

N/A

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

The study population lives in French Guiana in 3 different areas (Saül, Trois Sauts, and Cayenne and its surroundings), and eligible individuals (Populations 1 and 3) or those residing in a high-seroprevalence geographic area (Population 2) were identified by the National Reference Center (CNR) for Arboviruses at the Institut Pasteur of French Guiana (IPG) as part of arbovirus virological surveillance in French Guiana.

Description

Inclusion Criteria:

For all:

  • Adults (≥18 years old)
  • Willingness to participate in the study after explanation and signing of the informed consent form

Study population 1:

- Presenting a laboratory-confirmed OROV infection, defined by a positive real-time RT-PCR and/or positive seroneutralization performed as part of the management of and response to the 2020 OROV epidemic in Saül.

Study population 2:

- Residing in Trois-Sauts for at least 5 years

Study population 3:

- Presenting a laboratory-confirmed OROV infection, defined by a positive real-time RT-PCR and/or positive seroneutralization, identified in the Cayenne area and surrounding localities during the study period, as part of the surveillance activities of the CNR for Arboviruses (IPG).

Exclusion Criteria:

For all:

  • Pregnant women.
  • Individuals presenting with severe chronic pathologies (notably active cancer, primary or secondary immunodeficiency, immunosuppressive treatment, HIV infection, or autoimmune diseases), according to the information declared by the participants.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: OTHER
  • Time Perspectives: PROSPECTIVE

Cohorts and Interventions

Group / Cohort

Group / Cohort

A group or subgroup of participants in an observational study that is assessed for biomedical or health outcomes.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
adults with confirmed past OROV infection (2020) recruited from Saül
Other: 20 ml blood sample

A 20-ml blood sample
adults recruited from Trois-Sauts with ∼80% seroprevalence
Other: 20 ml blood sample

A 20-ml blood sample
newly confirmed OROV cases identified during the study period in the Cayenne region
Other: 20 ml blood sample

A 20-ml blood sample

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Characterization of the adaptive immune response to OROV infection during the convalescent phase.
Time Frame: 12 months

OROV-specific polyclonal antibodies will be detected in participants' plasma to confirm prior infection.
12 months

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Isolate OROV-specific B cells (recognizing the Gn_Gc antigenic complex) and generate human monoclonal antibodies by single B cell culture.
Time Frame: 12 months

Isolation of OROV-specific B cells by flow cytometry, followed by culture and stimulation of single B cells to generate and identify human monoclonal antibodies specific to OROV.
12 months
Screening of secreted mAbs using OROV antigens and VDJ sequencing to characterize immunoglobulin repertoires.
Time Frame: 12 months

secreted mAbs using OROV antigens and VDJ sequencing will be screened to characterize immunoglobulin repertoires.
12 months
Structural characterization of neutralizing mAbs by cryo-EM and nano-imaging to identify conserved epitopes.
Time Frame: 12 months

cryo-EM and nano-imaging will be performed on neutralizing mAbs to characterize structurally the mAbs
12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Institut Pasteur

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Institut Pasteur du Cambodge
CHU Guyane

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
November 30, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 30, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 30, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 2, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 2, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 6, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
November 6, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 2, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 2026-047_OROV-IMM
  • 2026-A01467-44 (Other Identifier: ID-RCB)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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