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1.
J Med Virol ; 93(10): 5816-5824, 2021 10.
Article in English | MEDLINE | ID: covidwho-1453607

ABSTRACT

Serological testing for anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies is used to detect ongoing or past SARS-CoV-2 infections. To study the kinetics of anti-SARS-CoV-2 antibodies and to assess the diagnostic performances of eight serological assays, we used 129 serum samples collected on known days post symptom onset (dpso) from 42 patients with polymerase chain reaction-confirmed coronavirus disease 2019 (COVID-19) and 54 serum samples from healthy blood donors, and children infected with seasonal coronaviruses. The sera were analyzed for the presence of immunoglobulin G (IgG), immunoglobulin M (IgM), and immunoglobulin A (IgA) antibodies using indirect immunofluorescence testing (IIFT) based on SARS-CoV-2-infected cells. They were further tested for antibodies against the S1 domain of the SARS-CoV-2 spike protein (IgG, IgA) and against the viral nucleocapsid protein (IgG, IgM) using enzyme-linked immunosorbent assays. The assay specificities were 94.4%-100%. The sensitivities varied largely between assays, reflecting their respective purposes. The sensitivities of IgA and IgM assays were the highest between 11 and 20 dpso, whereas the sensitivities of IgG assays peaked between 20 and 60 dpso. IIFT showed the highest sensitivities due to the use of the whole SARS-CoV-2 as substrate and provided information on whether or not the individual has been infected with SARS-CoV-2. Enzyme-linked immunosorbent assays provided further information about both the prevalence and concentration of specific antibodies against selected antigens of SARS-CoV-2.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing , COVID-19/blood , SARS-CoV-2/immunology , Adult , Aged , Aged, 80 and over , Antibodies, Viral/immunology , COVID-19/diagnosis , Coronavirus Nucleocapsid Proteins/immunology , Enzyme-Linked Immunosorbent Assay , Female , Fluorescent Antibody Technique, Indirect , Humans , Immunoglobulin Isotypes/blood , Kinetics , Male , Middle Aged , Phosphoproteins/immunology , SARS-CoV-2/isolation & purification , Sensitivity and Specificity , Spike Glycoprotein, Coronavirus/immunology
2.
Clin Microbiol Infect ; 2021 Sep 20.
Article in English | MEDLINE | ID: covidwho-1415295

ABSTRACT

OBJECTIVES: To investigate the response of the immune system (and its influencing factors) to vaccination with BNT162b2 or mRNA-1273. METHODS: 531 vaccinees, recruited from healthcare professionals, donated samples before, in between, and after the administration of the two doses of the vaccine. T- and B-cell responses were examined via interferon-γ (IFN-γ) release assay, and antibodies against different epitopes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) (S1 and NCP) were detected via ELISA and surrogate neutralization assay. Results were correlated with influencing factors such as age, sex, prior infection, vaccine received (BNT162b2 or mRNA-1273), and immunosuppression. Furthermore, antinuclear antibodies (ANAs) were measured to screen for autoimmune responses following vaccination with an mRNA vaccine. RESULTS: No markers of immunity against SARS-CoV-2 were found before the first vaccination. Two weeks after it, specific responses against SARS-CoV-2 were already measurable (median ± median absolute deviation (MAD): anti-S1 IgG 195.5 ± 172.7 BAU/mL; IgA 6.7 ± 4.9 OD; surrogate neutralization 39 ± 23.7%), and were significantly increased two weeks after the second dose (anti-S1 IgG 3744 ± 2571.4 BAU/mL; IgA 12 ± 0 OD; surrogate neutralization 100 ± 0%, IFN-γ 1897.2 ± 886.7 mIU/mL). Responses were stronger for younger participants (this difference decreasing after the second dose). Further influences were previous infection with SARS-CoV-2 (causing significantly stronger responses after the first dose compared to unexposed individuals (p ≤ 0.0001)) and the vaccine received (significantly stronger reactions for recipients of mRNA-1273 after both doses, p < 0.05-0.0001). Some forms of immunosuppression significantly impeded the immune response to the vaccination (with no observable immune response in three immunosuppressed participants). There was no significant induction of ANAs by the vaccination (no change in qualitative ANA results (p 0.2592) nor ANA titres (p 0.08) from pre-to post-vaccination. CONCLUSIONS: Both vaccines elicit strong and specific immune responses against SARS-CoV-2 which become detectable one week (T-cell response) or two weeks (B-cell response) after the first dose.

3.
Journal of Medical Virology ; 93(10):i-i, 2021.
Article in English | Wiley | ID: covidwho-1353578

ABSTRACT

Front Cover Caption: The cover image is based on the Research Article Longitudinal detection of SARS-CoV-2-specific antibody responses with different serological methods by Petra Emmerich et al., https://doi.org/10.1002/jmv.27113.

4.
Clin Chem Lab Med ; 59(5): 979-985, 2021 04 27.
Article in English | MEDLINE | ID: covidwho-1038531

ABSTRACT

OBJECTIVES: During the current pandemic, antibody testing based on venous serum helps to determine whether the tested person has been previously infected with SARS-CoV-2. Alternatively, capillary blood can be taken via a finger prick (dried blood spots, DBS). In this study, paired DBS and venipuncture samples were tested using two serological assays to evaluate the usability of DBS for the detection of anti-SARS-CoV-2 antibodies. METHODS: Paired samples of DBS and venous serum were collected from 389 volunteers, of whom 75 had a recent PCR-confirmed SARS-CoV-2 infection, and tested for anti-SARS-CoV-2 IgG antibodies against both viral S1 and nucleocapsid protein (NCP) antigens using two ELISAs. Degree of agreement and correlation coefficients between ELISA results based on the two sampling methods were calculated. RESULTS: Results of DBS showed almost perfect agreement and high correlations with results from corresponding serum samples in both the S1-based ELISA and the NCP-based ELISA. CONCLUSIONS: ELISA results derived from DBS showed very high agreement to those obtained with serum, supposing adequate usability and robustness of DBS as sample material for detection of anti-SARS-CoV-2 antibodies. In the near future, large-scale epidemiological screening for antibodies against SARS-CoV-2 will be carried out. Since DBS reduce the strain on healthcare institutions regarding sample collection, they have a potential to facilitate efficient community- and population-based screening in the current SARS-CoV-2 pandemic.


Subject(s)
Antibodies, Viral/blood , COVID-19/diagnosis , SARS-CoV-2/immunology , Antibodies, Viral/immunology , COVID-19/blood , COVID-19 Serological Testing/statistics & numerical data , Dried Blood Spot Testing/statistics & numerical data , Enzyme-Linked Immunosorbent Assay/statistics & numerical data , Humans , Linear Models , Specimen Handling
5.
J Pediatric Infect Dis Soc ; 9(5): 620-621, 2020 Nov 10.
Article in English | MEDLINE | ID: covidwho-919278

ABSTRACT

The reason for the apparently lower infection rate of children with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) compared to adults is still unclear. Here, we report on 4 schoolchildren with heavy exposure to SARS-CoV-2 with no clinical signs of coronavirus disease 2019, repeated negative nasopharyngeal swabs for SARS-CoV-2 RNA, and no seroconversion.


Subject(s)
Betacoronavirus , Coronavirus Infections/transmission , Family Health , Pneumonia, Viral/transmission , Betacoronavirus/isolation & purification , COVID-19 , Child , Disease Transmission, Infectious , Female , Humans , Male , Middle Aged , Pandemics , SARS-CoV-2
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