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Emerg Infect Dis ; 28(6)2022 Mar 31.
Article in English | MEDLINE | ID: covidwho-1771003


The SARS-CoV-2 Omicron variant BA.2 sublineage is rapidly replacing earlier Omicron lineages, suggesting BA.2 has increased vaccine evasion properties. We measured neutralization titers of authentic BA.1 and BA.2 isolates in serum samples from persons who received the BNT162b2 booster vaccine. All samples neutralized BA.1 and BA.2 at equal median values.

Sci Rep ; 11(1): 20323, 2021 10 13.
Article in English | MEDLINE | ID: covidwho-1467136


This study aimed to develop a highly sensitive SARS-CoV-2 nucleocapsid antigen assay using the single molecule array (Simoa) technology and compare it with real time RT-PCR as used in routine clinical practice with the ambition to achieve a comparative technical and clinical sensitivity. Samples were available from 148 SARS-CoV-2 real time RT-PCR positive and 73 SARS-CoV-2 real time RT-PCR negative oropharyngeal swabs. For determination of technical sensitivity SARS-CoV-2 virus culture material was used. The samples were treated with lysis buffer and analyzed using both an in-house and a pre-commercial SARS-CoV-2 nucleocapsid antigen assay on Simoa. Both nucleocapsid antigen assays have a technical sensitivity corresponding to around 100 SARS-CoV-2 RNA molecules/mL. Using a cut-off at 0.1 pg/mL the pre-commercial SARS-CoV-2 nucleocapsid antigen assay had a sensitivity of 96% (95% CI 91.4-98.5%) and specificity of 100% (95% CI 95.1-100%). In comparison the in-house nucleocapsid antigen assay had sensitivity of 95% (95% CI 89.3-98.1%) and a specificity of 100% (95% CI 95.1-100%) using a cut-off at 0.01 pg/mL. The two SARS-CoV-2 nucleocapsid antigen assays correlated with r = 0.91 (P < 0.0001). The in-house and the pre-commercial SARS-CoV-2 nucleocapsid antigen assay demonstrated technical and clinical sensitivity comparable to real-time RT-PCR methods for identifying SARS-CoV-2 infected patients and thus can be used clinically as well as serve as a reference method for antigen Point of Care Testing.

COVID-19/diagnosis , Coronavirus Nucleocapsid Proteins/immunology , SARS-CoV-2/immunology , Antigens, Viral/immunology , COVID-19 Serological Testing/methods , Coronavirus Nucleocapsid Proteins/analysis , Denmark , Diagnostic Tests, Routine , Humans , Immunoenzyme Techniques , Nasopharynx/virology , Nucleocapsid/analysis , Nucleocapsid/immunology , Phosphoproteins/analysis , Phosphoproteins/immunology , SARS-CoV-2/pathogenicity , Sensitivity and Specificity , Single Molecule Imaging/methods , Virion/chemistry
Clin Chem Lab Med ; 59(12): 1988-1997, 2021 Nov 25.
Article in English | MEDLINE | ID: covidwho-1376633


OBJECTIVES: We hypothesized that the amount of antigen produced in the body during a COVID-19 infection might differ between patients, and that maximum concentrations would predict the degree of both inflammation and outcome for patients. METHODS: Eighty-four hospitalized and SARS-CoV-2 PCR swab-positive patients, were followed with blood sampling every day until discharge or death. A total of 444 serial EDTA plasma samples were analyzed for a range of biomarkers: SARS-CoV-2 nuclear antigen and RNA concentration, complement activation as well as several inflammatory markers, and KL-6 as a lung marker. The patients were divided into outcome groups depending on need of respiratory support and death/survival. RESULTS: Circulating SARS-CoV-2 nuclear antigen levels were above the detection limit in blood in 65 out of 84 COVID-19 PCR swab-positive patients on day one of hospitalization, as was viral RNA in plasma in 30 out of 84. In all patients, complete antigen clearance was observed within 24 days. There were definite statistically significant differences between the groups depending on their biomarkers, showing that the concentrations of virus RNA and antigen were correlated to the inflammatory biomarker levels, respiratory treatment and death. CONCLUSIONS: Viral antigen is cleared in parallel with the virus RNA levels. The levels of antigens and SARS-CoV-2 RNA in the blood correlates with the level of IL-6, inflammation, respiratory failure and death. We propose that the antigens levels together with RNA in blood can be used to predict the severity of disease, outcome, and the clearance of the virus from the body.

C-Reactive Protein/analysis , COVID-19/pathology , Complement C3d/analysis , Interleukin-6/blood , Nucleocapsid/blood , RNA, Viral/blood , Adult , Aged , Aged, 80 and over , Biomarkers/blood , COVID-19/virology , Female , Hospitalization , Humans , Male , Middle Aged , Prognosis , RNA, Viral/metabolism , Retrospective Studies , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , SARS-CoV-2/physiology , Severity of Illness Index , Viral Load , Young Adult