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1.
COVID ; 2(6):752-758, 2022.
Article in English | MDPI | ID: covidwho-1884035

ABSTRACT

Background: Antigen tests for SARS-CoV-2 testing are rapid and inexpensive but usually have lower sensitivity than RT-qPCR and are only validated for nasopharyngeal/throat swabs;the latter are considered the gold standard in terms of material collection but are not tolerated by patients with frequent sampling. The present study, therefore, investigates the extent to which SARS-CoV-2 antigen testing is comparable to RT-qPCR from an easily obtained gargle solution compared to nasopharyngeal swabs. Methods: The performance of a high-quality POC fluorescence immune antigen test in single nasal swab samples and gargle samples compared to RT-qPCR was investigated (total n = 620 samples (gargle samples = 309, and nasal swabs = 311)). Findings: In our setting, the detection of SARS-CoV2 with an antigen test was reliable up to a Ct value of 30 for single nasal swab samples and was reduced to Ct:20 for single gargle samples. The overall antigen-test sensitivity is 83.92% (swab samples) and 75.72% (gargle samples). Interpretation: Antigen tests showed reliable results up to a detection limit of Ct: 30 with only nasal swab samples but not gargle samples. If the use of gargle samples is preferred due to their advantages, such as painless testing, easy handling, and the lack of a need to involve trained personnel for sample taking, reliable results can only be achieved with RT-qPCR.

2.
Lancet Rheumatol ; 4(5): e329-e337, 2022 May.
Article in English | MEDLINE | ID: covidwho-1764076

ABSTRACT

Background: Multisystem inflammatory syndrome in children (MIS-C) is a rare but serious complication of infection with SARS-CoV-2. A possible involvement of pathogenetically relevant autoantibodies has been discussed. Recently, neutralising autoantibodies against inflammatory receptor antagonists progranulin and interleukin-1 receptor antagonist (IL-1Ra) were found in adult patients with critical COVID-19. The aim of this study was to investigate the role of such autoantibodies in MIS-C. Methods: In this multicentre, retrospective, cohort study, plasma and serum samples were collected from patients (0-18 years) with MIS-C (as per WHO criteria) treated at five clinical centres in Germany and Spain. As controls, we included plasma or serum samples from children with Kawasaki disease, children with inactive systemic juvenile idiopathic arthritis, and children with suspected growth retardation (non-inflammatory control) across four clinical centres in Germany and Spain (all aged ≤18 years). Serum samples from the CoKiBa trial were used as two further control groups, from healthy children (negative for SARS-CoV-2 antibodies) and children with previous mild or asymptomatic COVID-19 (aged ≤17 years). MIS-C and control samples were analysed for autoantibodies against IL-1Ra and progranulin, and for IL-1Ra concentrations, by ELISA. Biochemical analysis of plasma IL-1Ra was performed with native Western blots and isoelectric focusing. Functional activity of the autoantibodies was examined by an in vitro IL-1ß-signalling reporter assay. Findings: Serum and plasma samples were collected between March 6, 2011, and June 2, 2021. Autoantibodies against IL-1Ra could be detected in 13 (62%) of 21 patients with MIS-C (11 girls and ten boys), but not in children with Kawasaki disease (n=24; nine girls and 15 boys), asymptomatic or mild COVID-19 (n=146; 72 girls and 74 boys), inactive systemic juvenile idiopathic arthritis (n=10; five girls and five boys), suspected growth retardation (n=33; 13 girls and 20 boys), or in healthy controls (n=462; 230 girls and 232 boys). Anti-IL-1Ra antibodies in patients with MIS-C belonged exclusively to the IgG1 subclass, except in one patient who had additional IL-1Ra-specific IgM antibodies. Autoantibodies against progranulin were only detected in one (5%) patient with MIS-C. In patients with MIS-C who were positive for anti-IL-1Ra antibodies, free plasma IL-1Ra concentrations were reduced, and immune-complexes of IL-1Ra were detected. Notably, an additional, hyperphosphorylated, transiently occurring atypical isoform of IL-1Ra was observed in all patients with MIS-C who were positive for anti-IL-1Ra antibodies. Anti-IL-1Ra antibodies impaired IL-1Ra function in reporter cell assays, resulting in amplified IL-1ß signalling. Interpretation: Anti-IL-1Ra autoantibodies were observed in a high proportion of patients with MIS-C and were specific to these patients. Generation of these autoantibodies might be triggered by an atypical, hyperphosphorylated isoform of IL-1Ra. These autoantibodies impair IL-1Ra bioactivity and might thus contribute to increased IL-1ß-signalling in MIS-C. Funding: NanoBioMed fund of the University of Saarland, José Carreras Center for Immuno and Gene Therapy, Dr Rolf M Schwiete Stiftung, Staatskanzlei Saarland, German Heart Foundation, Charity of the Blue Sisters, Bavarian Ministry of Health, the Center for Interdisciplinary Clinical Research at University Hospital Münster, EU Horizon 2020.

3.
EuropePMC; 2020.
Preprint in English | EuropePMC | ID: ppcovidwho-314910

ABSTRACT

Background: Children are affected rather mildly by the acute phase of COVID-19, but predominantly in children and youths, the potentially severe and life threatening pediatric multiorgan immune syndrome (PMIS) occurs later on. To identify children at risk early on, we searched for antibodies against SARS-CoV-2 and searched for early and mild symptoms of PMIS in those with high levels of antibodies. Methods: In a cross-sectional design, children aged 1-17 were recruited through primary care pediatricians for the study (a), if they had an appointment for a regular health check-up or (b), or if parents and children volunteered to participate in the study. Two antibody tests were performed in parallel and children with antibody levels >97th percentile (in the commercially available test) were screened for signs and symptoms of PMIS and SARS-CoV-2 neutralization tests were performed. Results: We identified antibodies against SARS-CoV-2 in 162 of 2832 eligible children (5.7%) between June and July 2020 in three, in part strongly affected regions of Bavaria. Approximately 60% of antibody positive children showed high levels of antibodies. In those who participated in the follow up screening, 30% showed some mild and minor symptoms similar to Kawasaki disease and in three children, cardiac and neuropsychological symptoms were identified. Symptoms correlated with high levels of non-neutralizing and concomitantly low levels of neutralizing antibodies and lower neutralizing capacity. Conclusions: Children exposed to SARS-CoV-2 should be screened for antibodies and those children with positive antibody responses should undergo a stepwise assessment for late COVID-19 effects.

4.
COVID ; 1(4):717-727, 2021.
Article in English | MDPI | ID: covidwho-1542442

ABSTRACT

(1) Background: With vaccination and new variants of SARS-CoV-2 on the horizon, efficient testing in schools may enable prevention of mass infection outbreaks, keeping schools safe places and buying time until decisions on feasibility and the necessity of vaccination in children and youth are made. We established, in the course of the WICOVIR (Where Is the COrona VIRus) study, that gargle-based pool-PCR testing offers a feasible, efficient, and safe testing system for schools in Germany when applied by central university laboratories. (2) Objectives: We evaluated whether this approach can be implemented in different rural and urban settings. (3) Methods: We assessed the arrangements required for successful implementation of the WICOVIR approach in a variety of settings in terms of transport logistics, data transfer and pre-existing laboratory set-up, as well as the time required to establish the set-up. (4) Results: We found that once regulatory issues have been overcome, all challenges pertaining to logistics, data transfer, and laboratory testing on different platforms can be solved within one month. Pooling and depooling of samples down to the individual test result were achievable within one working day in all settings. Local involvement of the community and decentralized set-ups were keys for success. (5) Conclusion: The WICOVIR gargle-based pool-PCR system is so robust and simple that it can be implemented within one month in all settings now or in future pandemics.

5.
Front Pediatr ; 9: 721518, 2021.
Article in English | MEDLINE | ID: covidwho-1518517

ABSTRACT

Background: Opening schools and keeping children safe from SARS-CoV-2 infections at the same time is urgently needed to protect children from direct and indirect consequences of the COVID-19 pandemic. To achieve this goal, a safe, efficient, and cost-effective SARS-CoV-2 testing system for schools in addition to standard hygiene measures is necessary. Methods: We implemented the screening WICOVIR concept for schools in the southeast of Germany, which is based on gargling at home, pooling of samples in schools, and assessment of SARS-CoV-2 by pool rRT-PCR, performed decentralized in numerous participating laboratories. Depooling was performed if pools were positive, and results were transmitted with software specifically developed for the project within a day. Here, we report the results after the first 13 weeks in the project. Findings: We developed and implemented the proof-of-concept test system within a pilot phase of 7 weeks based on almost 17,000 participants. After 6 weeks in the main phase of the project, we performed >100,000 tests in total, analyzed in 7,896 pools, identifying 19 cases in >100 participating schools. On average, positive children showed an individual CT value of 31 when identified in the pools. Up to 30 samples were pooled (mean 13) in general, based on school classes and attached school staff. All three participating laboratories detected positive samples reliably with their previously established rRT-PCR standard protocols. When self-administered antigen tests were performed concomitantly in positive cases, only one of these eight tests was positive, and when antigen tests performed after positive pool rRT-PCR results were already known were included, 3 out of 11 truly positive tests were also identified by antigen testing. After 3 weeks of repetitive WICOVIR testing twice weekly, the detection rate of positive children in that cohort decreased significantly from 0.042 to 0.012 (p = 0.008). Interpretation: Repeated gargle pool rRT-PCR testing can be implemented quickly in schools. It is an effective, valid, and well-received test system for schools, superior to antigen tests in sensitivity, acceptance, and costs.

6.
Front Pediatr ; 9: 678937, 2021.
Article in English | MEDLINE | ID: covidwho-1477849

ABSTRACT

Background: Children and youth are affected rather mildly in the acute phase of COVID-19 and thus, SARS-CoV-2 infection infection may easily be overlooked. In the light of current discussions on the vaccinations of children it seems necessary to better identify children who are immune against SARS-CoV-2 due to a previous infection and to better understand COVID-19 related immune reactions in children. Methods: In a cross-sectional design, children aged 1-17 were recruited through primary care pediatricians for the study (a) randomly, if they had an appointment for a regular health check-up or (b) if parents and children volunteered and actively wanted to participate in the study. Symptoms were recorded and two antibody tests were performed in parallel directed against S (in house test) and N (Roche Elecsys) viral proteins. In children with antibody response in either test, neutralization activity was determined. Results: We identified antibodies against SARS-CoV-2 in 162 of 2,832 eligible children (5.7%) between end of May and end of July 2020 in three, in part strongly affected regions of Bavaria in the first wave of the pandemic. Approximately 60% of antibody positive children (n = 97) showed high levels (>97th percentile) of antibodies against N-protein, and for the S-protein, similar results were found. Sufficient neutralizing activity was detected for only 135 antibody positive children (86%), irrespective of age and sex. Initial COVID-19 symptoms were unspecific in children except for the loss of smell and taste and unrelated to antibody responses or neutralization capacity. Approximately 30% of PCR positive children did not show seroconversion in our small subsample in which PCR tests were performed. Conclusions: Symptoms of SARS-CoV-2 infections are unspecific in children and antibody responses show a dichotomous structure with strong responses in many and no detectable antibodies in PCR positive children and missing neutralization activity in a relevant proportion of the young population.

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