Serological Response to SARS-Cov-2 Virus in Personnel of the Institut Bergonié in the Context of the COVID-19 Pandemic - PRO-SERO-COV
Phase: NA
Conditions: Sars-CoV2, Serum; Disease
Sponsor: Institut Bergonié

              
 
Version 2.0 of 25/09/2020 
 
Page 1 of 9 
 
ANTIBODY RESPONSE TO THE SARS-COV-2 VIRUS IN 
STAFF WORKING AT INSTITUT BERGONIÉ IN THE 
CONTEXT OF THE COVID-19 PANDEMIC 
 
PRO-SERO-COV study 
 
NCT04426006 
 
Interventional research protocol involving people 
Category 2 for minimal risks and obligations  
 
ID-RCB no. 2020-A01355-34 / IB no.: 2020-01 
Version no. 2.0 of 25/09/2020 
 
 
Principal investigator: 
Dr Brice RICHEZ 
Department of Anaesthesia and Intensive Care 
Anaesthetist 
Institut Bergonié 
 
229, cours de l’Argonne – 33076 BORDEAUX Cedex 
 
Phone: +33 (0)556 333 217 – Fax: +33 (0)556 333 330  
 
E-mail: b.richez@bordeaux.unicancer.fr 
 
Scientific managers 
Dr Francoise DURRIEU 
Department of Biopathology, Institut Bergonié 
Doctor, clinical biologist 
Prof. Simone MATHOULIN‐PELISSIER 
 
UREC, Institut Bergonié 
 
Head doctor of the Research and Clinical Epidemiology Unit (UREC) 
 
Dr Isabelle SOUBEYRAN 
Department of Biopathology, Institut Bergonié 
Pathology specialist 
Prof. Isabelle BALDI 
Occupational doctor 
INSERM U1219/EPICENE team, Université Bordeaux 
 
Research and Clinical Epidemiology Unit  
 
Carine BELLERA 
Institut 
Bergonié 
 
Biostatistician 
Carine LALET 
Institut 
Bergonié 
 
Head of Clinical Studies  
 
SPONSOR 
INSTITUT BERGONIÉ 

Institut Bergonié 
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SUMMARY 
 
TITLE OF THE STUDY 
Antibody response to the SARS-CoV-2 virus in staff working at Institut 
Bergonié in the context of the COVID-19 pandemic. 
ACRONYM 
PRO-SERO-COV 
SPONSOR 
Institut Bergonié, Bordeaux 
STUDY CATEGORY 
RIPH2 (category 2 interventional research protocol involving people: minimal 
risks and obligations) 
COORDINATING/PRINCIPAL 
INVESTIGATOR 
Dr Brice RICHEZ, Institut Bergonié 
SCIENTIFIC MANAGERS 
Dr Françoise DURRIEU, Institut Bergonié 
Prof. Simone MATHOULIN‐PELISSIER, Institut Bergonié 
Dr Isabelle SOUBEYRAN, Institut Bergonié 
Prof. Isabelle BALDI, INSERM U1219, EPICENE, Université Bordeaux 
NUMBER OF SITES PLANNED 
1 
NUMBER OF PARTICIPANTS 
Around 600 participants 
STUDY DURATION 
Inclusion period: around 3.5 months – until 30/09/2020 
Follow-up: 12 months 
Study duration: around 16 months 
INDICATIONS 
Staff working at Institut Bergonié during the COVID-19 pandemic and with 
varying exposure levels at work: staff in treatment units and staff in other 
units (cf. protocol for a definition of exposure typologies). 
STUDY RATIONALE 
After having been infected with SARS-CoV-2, the majority of individuals 
developed a measurable immune response through the production of 
antibodies against the virus.  
Serological tests for the SARS-CoV-2 virus are in development to detect 
antibodies in order to determine whether an individual has been in contact 
with the virus. These serological tests make it possible to detect specific 
(immunoglobulins: Ig) antibodies (Ac) produced by the body to fight SARS-
CoV-2 and could also have multiple uses, as recently highlighted by the French 
National Authority for Health (Haute Autorité de la Santé, HAS). Serological 
tests will not be able to determine whether the person is contagious or not 
(HAS 16 April 2020 and 1 May 2020).  
Those who have been in contact with the virus, who fought off the virus and 
who have no more symptoms are considered to be recovered, as for all acute 
viral infections.  
However, the presence of antibodies is not the same as immune protection 
(= immunity). In fact, although the presence of neutralising antibodies can be 
observed in some patients, there is still no correlation with protection. 
Assured medium-term, lasting or definitive protection is not guaranteed. 
Therefore, a recurring reinfection or reactivation of the virus cannot be ruled 
out, as is the case for other coronaviruses. Although the risk of developing 
severe forms in the event of reinfection is very low, a person who has 
antibodies would be susceptible to reinfection and thus infecting their social 
circle.  
Consequently, to date, serological tests have had a place in epidemiological 
monitoring and in identifying those who were or have been in contact with 

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the virus (as a complement to RT-PCR, which remains the first-line test for 
diagnosing the acute stage of COVID-19), but not for identifying those who 
are potentially protected against the virus. 
Serological tests are currently performed using diagnostic tests that are 
based on the ELISA (enzyme-linked immunosorbent assay) method that is 
available 
commercially. 
Other 
techniques, 
including 
immunochromatographic rapid tests and fully automated tests, are also in 
development and/or under evaluation. Furthermore, these tests have not 
yet been approved (awaiting approval from the National Reference Centre 
(CNR) at the Institut Pasteur). 
At first glance, Nouvelle Aquitaine is a region that has not been severely 
affected in terms of COVID-19 cases (6% prevalence rate) and Institut 
Bergonié has put in place strict exclusion measures for staff who have been in 
contact with the virus and isolation measures for those who may be affected 
by the virus.  
There are currently no recommendations for carrying out systematic 
serological tests for staff. However, the question of immune response for the 
population, especially populations in contact with vulnerable groups, such as 
those suffering from a chronic disease, like cancer, remains an important one. 
Understanding the evolution of this response over time can make it possible 
to answer unresolved questions. 
In addition, due to the COVID-19 pandemic, the situation can seem 
particularly exceptional and worrying. This situation can lead to a 
considerable state of anxiety, in particular among vulnerable populations and 
the healthcare professionals who support them.  
OBJECTIVES 
Primary objective  
To evaluate the antibody immune response to infection by the SARS-CoV-2 
virus in healthy members of staff who have volunteered to be included and 
work in an oncology healthcare facility, with different types of exposure: care 
unit staff and staff in other units. 
We are interested specifically in detecting IgG and IgM antibodies on inclusion 
using an ECLIA (electrochemiluminescence assay) or an ELISA (enzyme-linked 
immunosorbent assay) automated test. 
 
Secondary objectives 
1. To evaluate antibody immune response (IgG and IgM through ELISA) in 
staff at 3 and 12 months (overall and depending on the type of exposure). 
2. To evaluate the antibody immune response in staff using other antibody 
isotypes (IgA through ELISA) at inclusion, 3 and 12 months (overall and 
depending on the type of exposure) (subject to (i) approval of these tests 
by the National Reference Centre during the study period and (ii) a serum 
preservation period that is compatible with carrying out these tests).  
3. To evaluate antibody immune response in staff using different antibody 
isotypes (IgG, IgM) at inclusion, 3 and 12 months (overall and depending 
on the type of exposure) using a rapid diagnostic test (RDT), known as a 
“rapid cassette test”.  
4. To identify the kinetics of producing antibodies (IgG, IgM using 
ELISA/ECLIA) against the SARS-CoV-2 virus over 12 months (overall and 
depending on the type of exposure). 
5. To evaluate the immune response triggered against SARC-CoV-2 (IgG, IgM, 
possibly IgA, by ELISA/ECLIA) according to the biological criteria (rate of 
lymphocytes in particular), overall and depending on the type of staff 
exposure. 

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6. To identify COVID-19 infections at inclusion, 3 and 12 months. 
7. [Optional study] To evaluate the presence and evolution of anxiety 
disorders.  
STUDY OUTLINE 
A prospective, monocentric longitudinal cohort with blood samples and a self-
questionnaire (at inclusion, 3 and 12 months). 
INCLUSION CRITERIA 
1. Being 18 years old or above. 
2. Employed (temporary or permanent contract) since 17 March 2020 (at 
least), the date on which national lockdown measures were implemented 
in response to the COVID-19 pandemic. 
3. Signed information consent form. 
4. Those who are members of a French social security scheme in compliance 
with Article 1121‐11 of the French Public Health Code (Code de la Santé 
Publique). 
EXCLUSION CRITERIA 
1. Declaration of a known, active SARS-CoV-2 viral infection in the 10 days 
before signing the consent form. A known, active SARS-CoV-2 viral 
infection is defined by a positive result from an RT-PCR diagnostic test.  
2. Presence of known symptoms that indicate COVID-19 in the 10 days 
before signing the consent form: fever, tiredness, dry cough, shortness of 
breath, loss of taste and/or smell, headaches, stiffness, conjunctivitis or a 
cold, digestive problems (vomiting/diarrhea). 
3. Those who are unable to follow and comply with the research procedures 
for geographic, social or psychological reasons. 
4. Pregnant or breastfeeding women. 
5. Individuals in detention and those who are unable or in no fit state to give 
their consent. 
ROLL-OUT OF THE STUDY 
 
After the investigating doctor has verified the participant’s eligibility 
criteria and information, each participant signs a written consent form. 
They are scheduled for an inclusion visit according to a timetable and in a 
unique collection point. Each participant is included with a unique study 
number. 
 
A Registered Nurse takes the blood sample (two 5 ml tubes) and arranges 
the next appointment (3 and 12 months).  
 
Demographic, clinical, professional and exposure data were collected on 
inclusion and at each visit: 
o Sex, age, weight, height (only at inclusion), 
o Biological parameters: complete blood count.   
o Job and exposure before and after the start of the crisis and the 
implementation of lockdown (16/03/2020): role, remote 
working, etc. 
o Tests for the SARS-CoV-2 virus, if carried out, and results, 
o If COVID-19 is detected (more than 10 days before inclusion or 
during follow-up): symptoms and duration.  
 
[Optional study]: Collecting anxiety symptoms using a self-questionnaire 
during each visit.  
 
Data collection will be carried out in a database (Redcap), under the 
administration of the EPICENE (cancer and environment team, Prof. I 
Baldi) team at the INSERM U1219 unit and the Clinical Investigation 
Centre CIC-EC 14.01. 
EVALUATION CRITERIA 
Primary evaluation criteria 
 
The antibody immune response to a SARS-CoV-2 viral infection will be 
determined 
on 
inclusion 
by 
detecting 
specific 
antibodies 
(immunoglobulins: IgM and IgG) using the ELISA method, which enables 

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qualitative and semi-quantitative measures. These ELISA tests will be 
performed in the Institut Bergonié’s medical biology laboratory. 
 
First and foremost, the antibody status for total antibodies (IgG + IgM) 
by ECLIA will be categorised according to the following methods (cf. 
“Biological tests” section): 
o “Positive” serological status:  
 
optical density above the ECLIA positivity level, 
 
or optical density between the ECLIA positivity and 
negativity levels and optical density above the ELISA 
positivity level (IgG or IgM), 
 
or positive or negative response controls not available in 
ECLIA and optical density above the ELISA positivity level 
(IgG or IgM). 
o “Negative” serological status:  
 
optical density below the ECLIA negativity level, 
 
or optical density between the ECLIA positivity and 
negativity levels and optical density below the ELISA 
negativity level (IgG and IgM). 
o “Uncertain” serological status: optical density between the ECLIA 
positivity and negativity levels and optical density between the 
ELISA positivity and negativity levels (IgG and IgM). 
o “Non-interpretable” serological status: positive or negative 
response controls not available in ECLIA and positive or negative 
response controls not available in ELISA. 
 
The IgG serological status will be categorised according to the following 
methods:   
o “Positive” IgG serological status:           
 
optical density above the ECLIA positivity level and 
optical density above the ELISA IgG positivity level, 
 
or optical density between the ECLIA positivity and 
negativity levels and optical density above the ELISA IgG 
positivity level, 
 
or positive or negative response controls not available in 
ECLIA and optical density above the ELISA IgG positivity 
level. 
o “Negative” IgG antibody status:  
 
optical density below the ECLIA negativity level, 
 
or optical density between the ECLIA positivity and 
negativity levels and optical density below the ELISA IgG 
negativity level, 
 
or positive or negative response controls not available in 
ECLIA and optical density below the ELISA IgG negativity 
level. 
o “Uncertain” IgG serological status: optical density between the 
ECLIA positivity and negativity levels and optical density between 
the ELISA IgG positivity and negativity levels. 
o “Non-interpretable” IgG serological status: positive or negative 
response controls not available in ECLIA and IgG positive or 
negative response controls not available in ELISA. 
 
The IgM serological status will be categorised according to the following 
methods:   
o “Positive” IgM serological status:           
 
optical density above the ECLIA positivity level and 
optical density above the ELISA IgM positivity level, 

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 
or optical density between the ECLIA positivity and 
negativity levels and optical density above the ELISA IgM 
positivity level, 
 
or positive or negative response controls not available in 
ECLIA and optical density above the ELISA IgM positivity 
level. 
o “Negative” IgM serological status:  
 
optical density below the ECLIA negativity level, 
 
or optical density between the ECLIA positivity and 
negativity levels and optical density below the ELISA IgM 
negativity level, 
 
or ECLIA unavailable positive or negative response 
controls and optical density below the ELISA IgM 
negativity level. 
o “Uncertain” IgM serological status: optical density between the 
ECLIA positivity and negativity levels and optical density between 
the ELISA IgM positivity and negativity levels. 
o “Non-interpretable” IgM serological status: positive or negative 
response controls not available in ECLIA and IgM positive or 
negative response controls not available in ELISA. 
 
 
The choice of defining the principal evaluation criteria is based on HAS 
recommendations: 
the 
serological 
tests 
recommended 
should, 
preferably, make it possible to detect the IgM and IgG specific to viral 
antigens separately using the same test. Detecting IgA is optional based 
on current knowledge. This IgM/IgG configuration makes it possible to 
cover a larger antibody production period (earlier with IgMs and later 
with IgGs). Furthermore, each combination of isotype is likely to provide 
additional information on the infection status.   
Secondary evaluation criteria 
1. The antibody immune response to a SARS-CoV-2 viral infection at 3 months 
and 12 months will be evaluated like the principal evaluation criteria (ELISA 
method).  
2. The antibody immune response to a SARS-CoV-2 viral infection will also be 
determined using other antibody isotypes (IgA) (subject to (i) approval of 
these tests by the National Reference Centre during the study period and 
(ii) a serum preservation period that is compatible with carrying out these 
tests). The IgA antibody response will be evaluated according to the same 
methods for IgG and IgM antibody responses (cf. principal evaluation 
criteria).  
3. The antibody immune response to a SARS-CoV-2 viral infection will also be 
determined using other antibody isotypes (IgG and IgM) using a rapid 
diagnostic test (RDT), known as a “rapid cassette test”. The “by RDT” 
serological status will be categorised according to the following methods:  
o “Positive” RDT serological status: presence of antibodies and subtypes 
(IgG and/or IgM) 
o “Negative” RDT serological status: no antibodies 
o Uninterpretable RDT antibody result: non-contributive internal 
controls that do not make it possible to determine the result. The test 
will have to be repeated.  
4. With regard to the kinetics of producing antibodies (IgG, IgM, IgA) against 
the SARS-CoV-2 virus over 12 months, the concentration of each antibody 
will be described in longitudinal terms at inclusion, 3 and 12 months. 

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5. The immune response that fights SARS-CoV-2 (IgG, IgM and IgA by ELISA) 
will also be evaluated according to the following biological criteria: rate of 
lymphocytes, lymphocyte subgroups T, NK and B, as well as the rate of 
white blood cells, polymorphonuclear neutrophils and eosinophils and the 
haemoglobin rate. 
6. An active COVID-19 infection is defined by a positive result to molecular 
tests that detect the SARS-CoV-2 coronavirus genome through RT-PCR. It 
will be identified by the reporting of active COVID-19 infections (positive 
PCR test) at month 3 and month 12 for participants included (can be 
performed in lockdown or in the event that the virus has a resurgence at 
the end of the year). The study will complete information on exposure 
between the two periods depending on the epidemic context at the time. 
7. [Optional study]: Anxiety symptoms will be collected using a GAD-7 self-
questionnaire (Spitzer et al. 2006), the score of which varies from 0 to 21. 
The recommended level for estimating generalised anxiety is 10 points. 
BIOLOGICAL TESTS 
The platform for carrying out biological tests will be the biology department 
at Institut Bergonié (Dr F Durrieu) and the biopathology department (Dr I 
Soubeyran). 
ELISA and ECLIA IgM, IgG and possibly IgA tests 
 
The ELISA IgG tests will be performed with EuroImmun kits that detect 
SARS-CoV-2 spicule antigens. The reading is carried out at 450 nm on a 
Multiskan FC (ThermoScientific) microplate photometer. The ELISA IgM 
tests will be carried out using Epitope Diagnostic kits (EDI: awaiting 
validation by the CNR). The ELISA IgA tests can be carried out as soon as 
possible and once validated by the CNR. 
 
The positivity and negativity levels are determined by the response-
related optical density obtained through a positive control and at least 
one negative control, according to the kit.   
 
The intensity of the response to each serum tested is compared to these 
negativity and positivity levels and, in particular, for each antibody, the 
antibody response will be determined as follows:  
o “Positive” serological status: optical density above the positivity 
level, 
o “Negative” serological status: optical density below the negativity 
level, 
o “Uncertain” serological status: optical density between the 
positivity and negativity levels, 
o Uninterpretable result: unavailable positive or negative response 
control 
 
The 
total 
Ig 
automated 
test 
(IgG 
+ 
IgM) 
by 
ECLIA 
(electrochemiluminescence immunoassay) will be performed through the 
Cobas Pro E801 (Roche Diagnostic) module using the Elecsys Ac Anti-
SARS-CoV-2 reagent. The positivity level is determined using a reactive 
optical indication compared to a positive calibrator and a negative 
calibrator and is expressed as a sample/level connection (S/L connection). 
o S/L: < 1.0: non-reactive (negative for anti-SARS-CoV-2 antibodies) 
o S/L: ≥ 1.0: reactive (positive for anti-SARS-CoV-2 antibodies) 
 
These different tests are validated by the CNR in line with HAS 
recommendations and are approved in a laboratory in line with 
recommendations from Cofrac, the French accreditation committee (SH-
GTA-04).  

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 
In the event of detecting IgM, an RT-qPCR and PCR digital (ddPCR) test 
will be offered to each person.  
Rapid Diagnostic Test (RDT) 
 
The rapid test will be carried out on a COVID-19 Sign IgM/IgG cassette 
(ServiBio), which is awaiting approval. 
 
An EDTA tube makes it possible to have the results of the complete blood 
count to ensure that there has been no interference in the test. 
 
In the event of detecting IgM, an RT-qPCR and PCR digital (ddPCR) test 
will be offered to each person.  
 
Test by RT-PCR and test by digital PCR (Dr I Soubeyran) 
 
The sample will be taken with a nasopharyngeal swab. After extracting 
the viral RNA with the QIAamp Viral RNA Mini kit (Qiagen), an RT-qPCR 
analysis will be carried out with the TAQPATH 1-STEP RT-qPCR kit on the 
QuantStudio 5 system in line with the supplier recommendations.   
 
The RT-PCR test is currently the only one recommended for diagnosing a 
COVID-19 infection (HAS, 16/04/2020).  
 
The digital PCR is a recent and decisive technology. It makes it possible to 
obtain the absolute quantification of DNA by dividing it into several 
subunits (around 20,000) in the form of emulsion droplets.  In addition, it 
will be more sensitive than the RT-qPCR and suited to samples with a low 
viral load.  The utility of this technology compared to RT-qPCR has 
recently been highlighted in two publications (Suo T. et al. 2020; Dong L. 
et al. 2020), indicating the benefit of using ddPCR in uncertain or negative 
cases obtained through qPCR. Based on the same RNA, the ddPCR will be 
performed on the Bio-Rad system with 2019-nCoV CDC ddPCR Triplex 
Probe Assay kits in line with supplier recommendations. Comparing the 
results obtained from RT-qPCR and ddPCR makes it possible to assess the 
suitability of this latest technology in evaluating the contagiousness of 
staff carrying IgM.   
STATISTICAL CONSIDERATIONS 
Number of subjects:  
The inclusion duration will be a maximum of 6 months (we are aiming for 2-3 
months), thus making it possible to offer the study to all staff (temporary and 
permanent contracts) at the Institut (1,087 people). We are hoping for a 
maximum of 1,000 participants, but are estimating a possible participation 
rate of 75% in view of societal demands.  
A minimum of 460 participants is needed on inclusion to estimate a 5% 
proportion (low estimate) of people with a positive serological test (G or M) 
with a 2% exactness of estimates (Wald test method); 811 participants on 
inclusion would allow us to have an estimate of this proportion with 1.5% 
exactness. 
Analyses 
 
The demographic, clinical, professional and lifestyle characteristics at 
different points (inclusion, month 3 and month 12) will be described. 
 
A flow diagram of the participants will be given.  
 
The qualitative variables will be described using figures and percentages. 
The figures and percentages will be presented in the event of missing 
data.  
 
The quantitative variables will be described in terms of non-parametric 
statistics (minimum, first quartile (Q1), median, third quartile (Q3) and 
maximum), as well as based on the average and standard deviation in the 
event of normality of distribution.  

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IDMC 
 
Not applicable.  
OTHER POINTS 
 
The signed information consent form will be stored by the Occupational 
Medicine department at Institut Bergonié in a secure location. 
 
Individual results cannot be communicated to the staff directly until the 
tests have been officially validated by the health authorities; in this case, 
the results will be given confidentially by the occupational doctor or the 
principal investigator to those who want them. 
 
If an RT-PCR test is necessary, the result will be given by the prescriber of 
the examination in accordance with the national strategy that will be 
validated by HAS (report of 1 May 2020). 
Timetable of evaluation of volunteers in the PRO-SERO-COV study 
 
 
Inclusion 
3 months (+/-1 month 
from the initial 
sample) 
12 months (+/-1 month 
from the initial sample) 
Consent 
Inclusion and exclusion 
criteria 
+ 
 
 
Blood sample  
(2 tubes: dry + EDTA) 
+ 
+ 
+ 
Short questionnaire 
+ 
+ 
+ 
Self-questionnaire 
GAD-7 (optional) 
+ 
+ 
+ 
https://www.inspq.qc.ca/boite-outils-pour-la-surveillance-post-sinistre-des-impacts-sur-la-sante-mentale/instruments-de-mesure-
standardises/questionnaires/symptomes-d-anxiete