Study of the Immunological and Virological Response of Patients With COVID-19 and Presenting an Asymptomatic or Pauci-symptomatic Form (AMBUCOV) (AMBUCOV)

March 23, 2026 updated by: Assistance Publique - Hôpitaux de Paris

Study of the Immunological and Virological Response of Patients Infected With SARS-CoV-2 and Presenting an Asymptomatic or Pauci-symptomatic Form

The purpose of this study is to describe the immunological and virological response of patients infected with CoV-2-SARS and presenting an asymptomatic or mildly symptomatic form, in particular the innate and adaptive response as well as the virological clearance kinetics.

The research hypothesis is that patients with an ambulatory form of SARS-CoV-2 infection, whether asymptomatic or mildly symptomatic, are able to mount an innate and adaptive immunological response capable of rapidly clearing the virus, in contrast to severe forms in which an early deficit of type 1 IFN response has been demonstrated, possibly responsible for a defect in the control of viral replication in the blood.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

A new coronavirus (SARS-CoV-2) was identified in December 2019 in the Wuhan region of China and is currently causing a global pandemic.

The disease, named COVID-19, causes an influenza syndrome associated with respiratory signs, but there are also asymptomatic and pauci-symptomatic forms. Approximately 2 to 3% of patients, primarily patients with pre-existing chronic diseases and the elderly, develop a very severe form responsible for an acute respiratory distress syndrome (ARDS) that can lead to death.

It has been shown that patients with a severe and critical form had an impaired type 1 interferon response, with decreased plasma levels of IFN-alpha2 in the most severe patients compared to hospitalized patients with a moderate form, and undetectable levels of IFN-beta. This lack of type 1 IFN response was associated with greater viral persistence in the blood and an exaggerated inflammatory response mediated primarily by the NF-kB pathway.

Almost all studies published to date on immune system disruption during CoV-2-SARS infection included mainly hospitalized patients requiring oxygen therapy due to their severity, assessed at the time of clinical worsening.

Thus, there is no or little data on immunological response profiles, particularly on type 1 IFN response but also on other aspects of the immunological response (adaptive cellular and humoral immunity), and its relationship with viral clearance kinetics during ambulatory forms of SARS-CoV-2 infection, whereas these forms represent more than 95% of the clinical forms.

The asymptomatic and pauci-symptomatic forms managed on an outpatient basis represent the most common form of CoV-2-SARS infection, with a favourable outcome in almost all cases.

A better description and understanding of the immunological profile, including type 1 IFN response and viral clearance kinetics in saliva, blood and feces, during asymptomatic and mild clinical forms will allow the identification of the major players in the immune response against SARS-CoV-2, and thus better define the responses that are lacking in severe patients.

Study Type

Interventional

Enrollment (Actual)

57

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • France
    • Île-de-France Region
      • Paris, Île-de-France Region, France, 75014
        • Hôpital Cochin

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

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Adult patients
  • Nasopharyngeal PCR positive for SARS-CoV-2 within 48 hours prior to inclusion in the study protocol, carried out in one of the participating outpatient screening centers
  • Symptomatic patients (nasopharyngeal screening positive due to suggestive symptoms) or asymptomatic (nasopharyngeal screening positive due to screening after contact with a positive subject)
  • Patients who have been informed and signed the consent
  • Pregnant and breastfeeding women who may be included in the study.

Exclusion Criteria:

  • Patients with criteria for hospitalization at the time of diagnosis (seriousness criteria, impossibility of staying at home)
  • Non-consent or inability to obtain consent,
  • Patient with dementia or not authorized, for psychiatric reasons or intellectual failure, to receive information on the protocol and to give informed consent,
  • Patient under guardianship / curatorship

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

  • Primary Purpose: Diagnostic
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Symptomatic
40 symptomatic patients to COVID-19 infection
Diagnostic test: Blood count
Blood count at each visit
Diagnostic test: Blood collection
Blood collection to understanding of the immunological profile at each visit
Diagnostic test: Nasopharyngeal swab
Research of SARS-CoV-2 infection in nasopharyngeal swab by RT-PCR at day 8 and day 15
Diagnostic test: Saliva samples
Research of SARS-CoV-2 infection in saliva samples at each visit (excepted inclusion)
Diagnostic test: Faeces samples
Research of SARS-CoV-2 infection in faeces samples at day 3, day 15 and day 90
Genetic: Genetic blood collection
Collection to further research at each visit
Other: Data collection
Demographics, symptoms, biological constants
Experimental: Asymptomatic
40 asymptomatic patients to COVID-19 infection
Diagnostic test: Blood count
Blood count at each visit
Diagnostic test: Blood collection
Blood collection to understanding of the immunological profile at each visit
Diagnostic test: Nasopharyngeal swab
Research of SARS-CoV-2 infection in nasopharyngeal swab by RT-PCR at day 8 and day 15
Diagnostic test: Saliva samples
Research of SARS-CoV-2 infection in saliva samples at each visit (excepted inclusion)
Diagnostic test: Faeces samples
Research of SARS-CoV-2 infection in faeces samples at day 3, day 15 and day 90
Genetic: Genetic blood collection
Collection to further research at each visit
Other: Data collection
Demographics, symptoms, biological constants

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Interferon response
Time Frame: Up to 90 days
Concentration of type I, type II and type III Interferon in peripheral blood
Up to 90 days

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Immunology : cytokines
Time Frame: Up to 90 days
Concentration of IL-6, TNF-alpha, IL-8, calprotectin in peripheral blood
Up to 90 days
Immunology : cell population
Time Frame: Up to 90 days
Proportions of monocytes, B cells and T cells in peripheral blood
Up to 90 days
Immunology : proteins
Time Frame: Up to 90 days
Concentration of anaphylatoxins C3a and C5a in peripheral blood
Up to 90 days
Immunology : pathways
Time Frame: Up to 90 days
Screening for genetic mutations involved in the interferon pathway
Up to 90 days
Immunology : antibody response
Time Frame: Up to 90 days
Concentration of antibodies directed against spike protein and nucleocapsids
Up to 90 days
Virology : Nasopharyngeal Viral clearance kinetics
Time Frame: Up to 90 days
Viral clearance kinetics in nasopharyngeal samples
Up to 90 days
Virology : Saliva Viral clearance kinetics
Time Frame: Up to 90 days
Viral clearance kinetics in saliva
Up to 90 days
Virology : faeces viral clearance kinetics
Time Frame: Up to 90 days
Viral clearance kinetics in faeces
Up to 90 days
Virology : peripheral blood viral clearance kinetics
Time Frame: Up to 90 days
Viral clearance kinetics in peripheral blood
Up to 90 days
Virology : sequencing
Time Frame: Up to 90 days
Analysis of virus mutations, especially of the gene encoding spike protein
Up to 90 days

Collaborators and Investigators

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

Sponsor

Assistance Publique - Hôpitaux de Paris

Collaborators

URC-CIC Paris Descartes Necker Cochin
Fonds IMMUNOV

Investigators

  • Study Director: Solen KERNEIS, Doctor, Assistance Publique - Hôpitaux de Paris

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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 (Actual)

February 5, 2021

Primary Completion (Actual)

September 15, 2021

Study Completion (Actual)

September 15, 2021

Study Registration Dates

First Submitted

November 30, 2020

First Submitted That Met QC Criteria

January 7, 2021

First Posted (Actual)

January 11, 2021

Study Record Updates

Last Update Posted (Actual)

March 27, 2026

Last Update Submitted That Met QC Criteria

March 23, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • APHP201285
  • 2020-A03102-37 (Other Identifier: ID-RCB)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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