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.
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.
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
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
Hôpital Cochin
Paris, Île-de-France, France
Solen KERNEIS, Doctor, Study Director
Assistance Publique - Hôpitaux de Paris