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1.
Infect Dis Now ; 52(1): 23-30, 2022 Feb.
Article in English | MEDLINE | ID: covidwho-1661845

ABSTRACT

OBJECTIVES: Strasbourg University Hospital faced an important COVID-19 first wave from early March 2020. We performed a longitudinal prospective cohort study to describe clinical and virological data, exposure history to COVID-19, and adherence to strict hygiene standards during the first pandemic wave in 1497 workers undergoing a SARS-CoV-2 serological test at our hospital, with a follow up of serology result three months later. PATIENTS AND METHODS: A total of 1497 patients were enrolled from April 6 to May 7, 2020. Antibody response to SARS-CoV-2 was measured, and COVID-19 exposure routes were analyzed according to SARS-CoV-2 serological status. RESULTS: A total of 515 patients (34.4%) were seropositive, mainly medical students (13.2%) and assistant nurses (12.0%). A history of COVID-19 exposure in a professional and/or private setting was mentioned by 83.1% of seropositive subjects (P<0.05; odds ratio [OR]: 2.5; 95% confidence interval [CI]: 1.8-3.4). COVID-19 exposure factors associated with seropositive status were non-professional exposure (OR: 1.9, 95% CI: 1.3-2.7), especially outside the immediate family circle (OR: 2.2, 95% CI: 1.2-3.9) and contact with a COVID-19 patient (OR: 1.6; 95% CI: 1.1-2.2). Among professionally exposed workers, systematic adherence to strict hygiene standards was well observed, except for the use of a surgical mask (P<0.05, OR: 1.9, 95% CI: 1.3-2.8). Of those who reported occasionally or never wearing a surgical mask, nurses (25.7%), assistant nurses (16.2%), and medical students (11.7%) were predominant. CONCLUSION: Infection of staff members during the first pandemic wave in our hospital occurred after both professional and private COVID-19 exposure, underlining the importance of continuous training in strict hygiene standards.


Subject(s)
COVID-19 , SARS-CoV-2 , Hospitals, University , Humans , Pandemics , Personnel, Hospital , Prospective Studies
2.
2021.
Preprint in English | Other preprints | ID: ppcovidwho-294752

ABSTRACT

Assessment of the kinetics of SARS-CoV-2 antibodies is essential in predicting protection against reinfection and durability of vaccine protection. Here, we longitudinally measured Spike (S) and Nucleocapsid (N)-specific antibodies in 1,309 healthcare workers (HCWs), including 916 COVID-19 negative HCWs and 393 convalescent COVID-19 for up to 422 days post-symptom. From month (M)1 to M7-9 post-infection, SARS-CoV-2 antibodies decreased moderately in convalescent HCWs in a biphasic model, with men showing a slower decay of anti-N (p=0.02), and a faster decay of anti-S (p=0.0008) than women. At M11-13, anti-N dramatically decreased (half-life: 283 days) while anti-S stabilized (half-life: 725 days) at a median of 2.39 log Arbitrary Units (AU)/mL (Interquartile Range (IQR): 2.10 -2.75). Overall, 69 SARS-CoV-2 infections developed in the COVID-19 negative group (incidence of 12.22 per 100 person-years) versus one in the COVID-19 positive group (incidence of 0.40 per 100 person-years), indicating a relative reduction in the incidence of SARS-CoV-2 reinfection of 96.7% (p<0.0001). Correlation with live-virus neutralization assay revealed that variants D614G and B.1.1.7, but not B.1.351, were sensitive to anti-S antibodies at 2.3 log AU/mL, while IgG ≥ 3 log AU/mL neutralized all three variants. After SARS-CoV-2 vaccination, anti-S levels reached at least 3 logs regardless of pre-vaccination IgG levels, type of vaccine, and number of doses. Our study demonstrates a long-term persistence of anti-S IgG antibodies that may protect against reinfection. By significantly increasing cross-neutralizing antibody titers, a single-dose vaccination strengthens protection against escape mutants.

3.
J Infect Dis ; 224(6): 983-988, 2021 09 17.
Article in English | MEDLINE | ID: covidwho-1455308

ABSTRACT

We measured anti-spike (S), nucleoprotein (N), and neutralizing antibodies in sera from 308 healthcare workers with a positive reverse-transcription quantitative polymerase chain reaction result for severe acute respiratory syndrome coronavirus 2 and with mild disease, collected at 2 timepoints up to 6 months after symptom onset. At month 1, anti-S and -N antibody levels were higher in male participants aged >50 years and participants with a body mass index (BMI) >25 kg/m2. At months 3-6, anti-S and anti-N antibodies were detected in 99% and 59% of individuals, respectively. Anti-S antibodies and neutralizing antibodies declined faster in men than in women, independent of age and BMI, suggesting an association of sex with evolution of the humoral response.


Subject(s)
Antibodies, Neutralizing/blood , COVID-19/immunology , Sex Characteristics , Adult , Antibodies, Viral/blood , Female , HEK293 Cells , Health Personnel , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/immunology
4.
EBioMedicine ; 71: 103561, 2021 Sep.
Article in English | MEDLINE | ID: covidwho-1372964

ABSTRACT

BACKGROUND: Assessment of the kinetics of SARS-CoV-2 antibodies is essential in predicting risk of reinfection and durability of vaccine protection. METHODS: This is a prospective, monocentric, longitudinal, cohort clinical study. Healthcare workers (HCW) from Strasbourg University Hospital were enrolled between April 6th and May 7th, 2020 and followed up to 422 days. Serial serum samples were tested for antibodies against the Receptor Binding Domain (RBD) of the spike protein and nucleocapsid protein (N) to characterize the kinetics of SARS-CoV-2 antibodies and the incidence of reinfection. Live-neutralization assays were performed for a subset of samples before and after vaccination to analyze sensitivity to SARS-CoV-2 variants. FINDINGS: A total of 4290 samples from 393 convalescent COVID-19 and 916 COVID-19 negative individuals were analyzed. In convalescent individuals, SARS-CoV-2 antibodies followed a triphasic kinetic model with half-lives at month (M) 11-13 of 283 days (95% CI 231-349) for anti-N and 725 days (95% CI 623-921) for anti-RBD IgG, which stabilized at a median of 1.54 log BAU/mL (95% CI 1.42-1.67). The incidence of SARS-CoV-2 infections was 12.22 and 0.40 per 100 person-years in COVID-19-negative and COVID-19-positive HCW, respectively, indicating a relative reduction in the incidence of SARS-CoV-2 reinfection of 96.7%. Live-virus neutralization assay revealed that after one year, variants D614G and B.1.1.7, but less so B.1.351, were sensitive to anti-RBD antibodies at 1.4 log BAU/mL, while IgG ≥ 2.0 log BAU/mL strongly neutralized all three variants. These latter anti-RBD IgG titers were reached by all vaccinated HCW regardless of pre-vaccination IgG levels and type of vaccine. INTERPRETATION: Our study demonstrates a long-term persistence of anti-RBD antibodies that may reduce risk of reinfection. By significantly increasing cross-neutralizing antibody titers, a single-dose vaccination strengthens protection against variants. FUN1DING: None.


Subject(s)
COVID-19/pathology , Immunity, Humoral , Reinfection/pathology , Adult , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Antibodies, Viral/immunology , Antibodies, Viral/metabolism , COVID-19/immunology , COVID-19/virology , COVID-19 Vaccines/administration & dosage , COVID-19 Vaccines/immunology , Coronavirus Nucleocapsid Proteins/immunology , Female , Humans , Immunoglobulin G/blood , Immunoglobulin G/immunology , Immunoglobulin G/metabolism , Kinetics , Longitudinal Studies , Male , Middle Aged , Phosphoproteins/immunology , Prospective Studies , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/immunology , Time Factors
5.
Diagn Microbiol Infect Dis ; 98(4): 115181, 2020 Dec.
Article in English | MEDLINE | ID: covidwho-725737

ABSTRACT

Rapid and accurate diagnosis is crucial for successful outbreak containment. During the current coronavirus disease 2019 (COVID-19) public health emergency, the gold standard for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection diagnosis is the detection of viral RNA. Additional diagnostic methods õenabling the detection of current or past SARS-CoV-2 infection would be highly beneficial. We assessed 2 immunochromatographic lateral flow assays (LFA-1, LFA-2) and 2 enzyme-linked immunosorbent assay kits (IgA/IgG ELISA-1, IgM/IgG ELISA-2) using 325 samples: serum samples from polymerase chain reaction-confirmed COVID-19 hospitalized patients (n = 55) and healthcare workers (n = 143) and 127 samples from negative controls. Diagnostic performances were assessed according to days after symptom onset (dso) and the antigenic format used by manufacturers. Clinical sensitivities varied greatly among the assays, showing poor mutual agreement. After 15 dso, ELISA-1 (Euroimmun) and LFA-1 (Biosynex) combining IgM and IgG detection showed the best performances. A thorough selection of serological assays for the detection of ongoing or past infections is advisable.


Subject(s)
Antibodies, Viral/blood , Clinical Laboratory Techniques/methods , Coronavirus Infections/diagnosis , Enzyme-Linked Immunosorbent Assay/methods , Immunoassay/methods , Mass Screening/methods , Pneumonia, Viral/diagnosis , Adult , Aged , Aged, 80 and over , Betacoronavirus/immunology , COVID-19 , COVID-19 Testing , Female , Humans , Immunoglobulin A/blood , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Pandemics , Polymerase Chain Reaction , RNA, Viral/analysis , SARS-CoV-2 , Sensitivity and Specificity , Young Adult
6.
EBioMedicine ; 59: 102915, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-691414

ABSTRACT

BACKGROUND: The serologic response of individuals with mild forms of SARS-CoV-2 infection is poorly characterized. METHODS: Hospital staff who had recovered from mild forms of PCR-confirmed SARS-CoV-2 infection were tested for anti-SARS-CoV-2 antibodies using two assays: a rapid immunodiagnostic test (99.4% specificity) and the S-Flow assay (~99% specificity). The neutralizing activity of the sera was tested with a pseudovirus-based assay. FINDINGS: Of 162 hospital staff who participated in the investigation, 160 reported SARS-CoV-2 infection that had not required hospital admission and were included in these analyses. The median time from symptom onset to blood sample collection was 24 days (IQR: 21-28, range 13-39). The rapid immunodiagnostic test detected antibodies in 153 (95.6%) of the samples and the S-Flow assay in 159 (99.4%), failing to detect antibodies in one sample collected 18 days after symptom onset (the rapid test did not detect antibodies in that patient). Neutralizing antibodies (NAbs) were detected in 79%, 92% and 98% of samples collected 13-20, 21-27 and 28-41 days after symptom onset, respectively (P = 0.02). INTERPRETATION: Antibodies against SARS-CoV-2 were detected in virtually all hospital staff sampled from 13 days after the onset of COVID-19 symptoms. This finding supports the use of serologic testing for the diagnosis of individuals who have recovered from SARS-CoV-2 infection. The neutralizing activity of the antibodies increased overtime. Future studies will help assess the persistence of the humoral response and its associated neutralization capacity in recovered patients. FUNDINGS: The funders had no role in study design, data collection, interpretation, or the decision to submit the work for publication.


Subject(s)
Antibodies, Viral/blood , Coronavirus Infections/diagnosis , Pneumonia, Viral/diagnosis , Adult , Antibodies, Neutralizing/blood , Betacoronavirus/genetics , Betacoronavirus/isolation & purification , COVID-19 , Coronavirus Infections/pathology , Coronavirus Infections/virology , Female , France , Health Personnel , Hospitals , Humans , Male , Middle Aged , Pandemics , Pneumonia, Viral/pathology , Pneumonia, Viral/virology , RNA, Viral/metabolism , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Serologic Tests , Severity of Illness Index
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