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1.
Euro Surveill ; 26(44)2021 Nov.
Article in English | MEDLINE | ID: covidwho-1504717

ABSTRACT

IntroductionNumerous CE-marked SARS-CoV-2 antigen rapid diagnostic tests (Ag RDT) are offered in Europe, several of them with unconfirmed quality claims.AimWe performed an independent head-to-head evaluation of the sensitivity of SARS-CoV-2 Ag RDT offered in Germany.MethodsWe addressed the sensitivity of 122 Ag RDT in direct comparison using a common evaluation panel comprised of 50 specimens. Minimum sensitivity of 75% for panel specimens with a PCR quantification cycle (Cq) ≤ 25 was used to identify Ag RDT eligible for reimbursement in the German healthcare system.ResultsThe sensitivity of different SARS-CoV-2 Ag RDT varied over a wide range. The sensitivity limit of 75% for panel members with Cq ≤ 25 was met by 96 of the 122 tests evaluated; 26 tests exhibited lower sensitivity, few of which failed completely. Some RDT exhibited high sensitivity, e.g. 97.5 % for Cq < 30.ConclusionsThis comparative evaluation succeeded in distinguishing less sensitive from better performing Ag RDT. Most of the evaluated Ag RDT appeared to be suitable for fast identification of acute infections associated with high viral loads. Market access of SARS-CoV-2 Ag RDT should be based on minimal requirements for sensitivity and specificity.


Subject(s)
COVID-19 , SARS-CoV-2 , Antigens, Viral , Diagnostic Tests, Routine , Germany , Humans , Sensitivity and Specificity
2.
Euro Surveill ; 26(44)2021 11.
Article in English | MEDLINE | ID: covidwho-1504591

ABSTRACT

IntroductionThe detection of SARS-CoV-2 with rapid diagnostic tests (RDT) has become an important tool to identify infected people and break infection chains. These RDT are usually based on antigen detection in a lateral flow approach.AimWe aimed to establish a comprehensive specimen panel for the decentralised technical evaluation of SARS-CoV-2 antigen rapid diagnostic tests.MethodsWhile for PCR diagnostics the validation of a PCR assay is well established, there is no common validation strategy for antigen tests, including RDT. In this proof-of-principle study we present the establishment of a panel of 50 pooled clinical specimens that cover a SARS-CoV-2 concentration range from 1.1 × 109 to 420 genome copies per mL of specimen. The panel was used to evaluate 31 RDT in up to six laboratories.ResultsOur results show that there is considerable variation in the detection limits and the clinical sensitivity of different RDT. We show that the best RDT can be applied to reliably identify infectious individuals who present with SARS-CoV-2 loads down to 106 genome copies per mL of specimen. For the identification of infected individuals with SARS-CoV-2 loads corresponding to less than 106 genome copies per mL, only three RDT showed a clinical sensitivity of more than 60%.ConclusionsSensitive RDT can be applied to identify infectious individuals with high viral loads but not to identify all infected individuals.


Subject(s)
COVID-19 , SARS-CoV-2 , Antigens, Viral , Diagnostic Tests, Routine , Humans , Sensitivity and Specificity , Serologic Tests
3.
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
4.
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.

5.
Trop Med Int Health ; 26(6): 621-631, 2021 06.
Article in English | MEDLINE | ID: covidwho-1119265

ABSTRACT

OBJECTIVES: Specific serological tests are mandatory for reliable SARS-CoV-2 diagnostics and seroprevalence studies. Here, we assess the specificities of four commercially available SARS-CoV-2 IgG ELISAs in serum/plasma panels originating from Africa, South America, and Europe. METHODS: 882 serum/plasma samples collected from symptom-free donors before the COVID-19 pandemic in three African countries (Ghana, Madagascar, Nigeria), Colombia, and Germany were analysed with three nucleocapsid-based ELISAs (Euroimmun Anti-SARS-CoV-2-NCP IgG, EDI™ Novel Coronavirus COVID-19 IgG, Mikrogen recomWell SARS-CoV-2 IgG), one spike/S1-based ELISA (Euroimmun Anti-SARS-CoV-2 IgG), and in-house common cold CoV ELISAs. RESULTS: High specificity was confirmed for all SARS-CoV-2 IgG ELISAs for Madagascan (93.4-99.4%), Colombian (97.8-100.0%), and German (95.9-100.0%) samples. In contrast, specificity was much lower for the Ghanaian and Nigerian serum panels (Ghana: NCP-based assays 77.7-89.7%, spike/S1-based assay 94.3%; Nigeria: NCP-based assays 39.3-82.7%, spike/S1-based assay 90.7%). 15 of 600 African sera were concordantly classified as positive in both the NCP-based and the spike/S1-based Euroimmun ELISA, but did not inhibit spike/ACE2 binding in a surrogate virus neutralisation test. IgG antibodies elicited by previous infections with common cold CoVs were found in all sample panels, including those from Madagascar, Colombia, and Germany and thus do not inevitably hamper assay specificity. Nevertheless, high levels of IgG antibodies interacting with OC43 NCP were found in all 15 SARS-CoV-2 NCP/spike/S1 ELISA positive sera. CONCLUSIONS: Depending on the chosen antigen and assay protocol, SARS-CoV-2 IgG ELISA specificity may be significantly reduced in certain populations probably due to interference of immune responses to endemic pathogens like other viruses or parasites.


Subject(s)
Antibodies, Viral/blood , COVID-19/diagnosis , Enzyme-Linked Immunosorbent Assay/methods , Immunoglobulin G/blood , Adolescent , Adult , COVID-19/virology , Child , Child, Preschool , Colombia , Coronavirus Nucleocapsid Proteins/immunology , Female , Germany , Ghana , Humans , Madagascar , Male , Middle Aged , Nigeria , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , Sensitivity and Specificity , Spike Glycoprotein, Coronavirus/immunology , Young Adult
6.
Deutsche Medizinische Wochenschrift ; 2020.
Article in German | MEDLINE | ID: covidwho-615176

ABSTRACT

BACKGROUND: In children, the infection with SARS-CoV-2, the cause of COVID-19, tends to be clinically inapparent more often or less severe than in adults. The spread of this infection from children poses a danger to vulnerable adults. Therefore, child care institutions and schools currently are widely closed. METHODS: Since the status of infection tends to be congruent in mothers and their children, we tested 401 mothers of children between 1 and 10 years in the city of Rostock (State of Mecklenburg-Westpomerania, northeast of Germany), for the presence of RNA of SARS-CoV-2 in throat swabs, and of antibodies against SARS-CoV-2 in serum. RESULTS: In none of the mothers tested, RNA of this virus was detected in the throat swab. In the ELISA test, IgG antibodies were positive in one serum sample, IgA antibodies were positive in 11, and borderline in 3 serum samples. All 401 sera were negative in the indirect immunofluorescence test (IIFT) with FITC-labeled IgG, IgA, und IgM antibodies. CONCLUSION: At the time of this study, neither SARS-CoV-2 RNA, nor specific antibodies against SARS-CoV-2 were detectable in the mothers tested in Rostock.

7.
Dtsch Med Wochenschr ; 145(17): e96-e100, 2020 08.
Article in German | MEDLINE | ID: covidwho-612422

ABSTRACT

BACKGROUND: In children, the infection with SARS-CoV-2, the cause of COVID-19, tends to be clinically inapparent more often or less severe than in adults. The spread of this infection from children poses a danger to vulnerable adults. Therefore, child care institutions and schools currently are widely closed. METHODS: Since the status of infection tends to be congruent in mothers and their children, we tested 401 mothers of children between 1 and 10 years in the city of Rostock (State of Mecklenburg-Westpomerania, northeast of Germany), for the presence of RNA of SARS-CoV-2 in throat swabs, and of antibodies against SARS-CoV-2 in serum. RESULTS: In none of the mothers tested, RNA of this virus was detected in the throat swab. In the ELISA test, IgG antibodies were positive in one serum sample, IgA antibodies were positive in 11, and borderline in 3 serum samples. All 401 sera were negative in the indirect immunofluorescence test (IIFT) with FITC-labeled IgG, IgA, und IgM antibodies. CONCLUSION: At the time of this study, neither SARS-CoV-2 RNA, nor specific antibodies against SARS-CoV-2 were detectable in the mothers tested in Rostock.


Subject(s)
Antibodies, Viral/blood , Betacoronavirus/immunology , Coronavirus Infections/epidemiology , Pneumonia, Viral/epidemiology , Adolescent , Adult , Aged , Aged, 80 and over , Betacoronavirus/genetics , Betacoronavirus/isolation & purification , COVID-19 , Child , Child, Preschool , Coronavirus Infections/diagnosis , Coronavirus Infections/immunology , Enzyme-Linked Immunosorbent Assay , Female , Fluorescent Antibody Technique, Indirect , Germany/epidemiology , Humans , Infant , Male , Mass Screening/methods , Middle Aged , Oropharynx/virology , Pandemics , Pneumonia, Viral/diagnosis , Pneumonia, Viral/immunology , Polymerase Chain Reaction , Prevalence , RNA, Viral/analysis , SARS-CoV-2 , Young Adult
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