Symptoms and immunoglobulin development in hospital staff exposed to a SARS-CoV-2 outbreak.

Worldwide, the number of SARS-CoV-2 infections is increasing. Serological immunoglobulin tests may help to better understand the development of immune mechanisms against SARS-CoV-2 in COVID-19 cases and exposed but asymptomatic individuals. The aim of this study was to investigate exposure to SARS-CoV-2, symptoms, and antibody responses in a large sample of healthcare workers following a COVID-19 outbreak. A COVID-19 outbreak among staff members of a major German children's and women's hospital was followed by massive RT-PCR SARS-CoV-2 tests and provided the opportunity to study symptoms, chains of infection, and SARS-CoV-2-specific antibody responses (IgG and IgA) by ELISA. Study participants were classified as COVID-19 cases, and persons with close, moderate, or no exposure to SARS-CoV-2 in the clinical setting, respectively. Out of 201 study participants, 31 were COVID-19 cases. While most study participants experienced many symptoms indicative for SARS-CoV-2 infection, anosmia and coughing were remarkably more frequent in COVID-19 cases. Approximately 80% of COVID-19 cases developed some specific antibody response (IgA and IgG) approximately 3 weeks after onset of symptoms. Subjects in the non-COVID-19 groups had also elevated IgG (1.8%) and IgA values (7.6%) irrespective of contact history with cases. We found that a significant number of diseased did not develop relevant antibody responses three weeks after symptom onset. Our data also suggest that exposure to COVID-19 positive co-workers in a hospital setting is not leading to the development of measurable immune responses in a significant proportion of asymptomatic contact persons.

Brandstetter S ，Roth S ，Harner S ，Buntrock-Döpke H ，Toncheva AA ，Borchers N ，Gruber R ，Ambrosch A ，Kabesch M ... -  《-》

Antibody response using six different serological assays in a completely PCR-tested community after a coronavirus disease 2019 outbreak-the CoNAN study.

Weis S ，Scherag A ，Baier M ，Kiehntopf M ，Kamradt T ，Kolanos S ，Ankert J ，Glöckner S ，Makarewicz O ，Hagel S ，Bahrs C ，Kimmig A ，Proquitté H ，Guerra J ，Rimek D ，Löffler B ，Pletz MW ，CoNAN Study Group ... -  《-》

Analytical and clinical validation of an ELISA for specific SARS-CoV-2 IgG, IgA, and IgM antibodies.

The development of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological tests is massive. The external validation of their performance is needed before use in clinical routine practice. Our study aims at assessing the analytical and clinical performance of two enzyme-linked immunosorbent assay tests detecting antibodies directed against the virus nucleocapsid protein: The NovaLisa SARS-CoV-2 immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM) test (NovaTec) allowing a separate detection of each antibody and the Platelia SARS-CoV-2 Total Ab test (Bio-Rad) detecting total antibodies (IgM, IgA, and IgG). Two-hundred and eight coronavirus disease 2019 samples from 48 quantitative reverse transcription-polymerase chain reaction (RT-qPCR) confirmed patients were used to perform the sensitivity analysis. Non-SARS-CoV-2 sera (n = 79) with a potential cross-reaction to SARS-CoV-2 immunoassays were included in the specificity analysis. In addition, using receiver operator characteristic curves, adapted cut-off for improvement of the performances were proposed. The kinetics of these antibodies was also assessed over 8 weeks. Two weeks after the RT-qPCR positive detection, the NovaLisa test shows a sensitivity and specificity of 94.9% (95% confidence interval [CI]: 83.1%-98.6%) and 96.2% (95% CI: 89.4%-98.7%) for IgG, of 89.7% (95% CI: 76.4%-95.9%) and 98.7% (95% CI: 93.2%-98.8%) for IgA, and of 48.7% (95% CI: 33.9%-63.8%) and 98.7% (95% CI: 93.2%-99.8%) for IgM. With the Platelia system, the specificity and sensitivity were 97.4% (95% CI: 92.1%-99.7%) and 94.9% (95% CI: 87.7%-98.0%) for total antibodies using the adapted cut-offs. The NovaLisa and the Platelia tests have satisfactory analytical performances. The clinical performances are excellent for IgG, IgA, and total antibodies especially if the cut-off is optimized.

Tré-Hardy M ，Wilmet A ，Beukinga I ，Favresse J ，Dogné JM ，Douxfils J ，Blairon L ... -  《-》

SARS-CoV-2 Seroprevalence in Healthcare Workers of Kaunas Hospitals during the First Wave of the COVID-19 Pandemic.

Pereckaitė L ，Dambrauskienė A ，Urbonienė D ，Sadauskas S ，Petrikonis K ，Naudžiūnas A ，Vitkauskienė A ... -  《-》

Seroprevalence of SARS-CoV-2 IgG antibodies in the current COVID-19 pandemic amongst co-workers at a UK renal transplant centre.

Black JT ，Haroon U ，Barnes SC ，Mayaleh S ，Bagul A ... -  《-》