Preanalytical stability of SARS-CoV-2 anti-nucleocapsid antibodies.

OBJECTIVES: Anti-nucleocapsid (NC) antibodies are produced in response to SARS-CoV-2 infection. Therefore, they are well suited for the detection of a previous infection. Especially in the case of seroprevalence studies or during the evaluation of a novel in-vitro diagnostic test, samples have been stored at <-70 °C (short- and long-term) or 2-10 °C (short-term) before analysis. This study aimed to assess the impact of different storage conditions relevant to routine biobanking on anti-NC antibodies. METHODS: The preanalytical impact of short-term storage (84 [58-98] days) on <-70 °C and for 14 days at 2-10 °C was evaluated using samples from 111 donors of the MedUni Vienna Biobank. Long-term effects (443 [409-468] days) were assessed using 208 samples from Biobank Graz and 49 samples from Biobank Vienna. Anti-Nucleocapsid antibodies were measured employing electrochemiluminescence assays (Roche Anti-SARS-CoV-2). RESULTS: After short-term storage, the observed changes did not exceed the extent that could be explained by analytical variability. In contrast, results after long-term storage were approximately 20% higher and seemed to increase with storage duration. This effect was independent of the biobank from which the samples were obtained. Accordingly, the sensitivity increased from 92.6 to 95.3% (p=0.008). However, comparisons with data from Anti-Spike protein assays, where these deviations were not apparent, suggest that this deviation could also be explained by the analytical variability of the qualitative Anti-NC assay. CONCLUSIONS: Results from anti-NC antibodies are stable during short-term storage at <-70 °C and 2-10 °C. After long-term storage, a slight increase in sensitivity could not be ruled out.

Isavuconazole plasma concentrations in critically ill patients during extracorporeal membrane oxygenation.

BACKGROUND: Isavuconazole is an antifungal drug used for treatment of invasive fungal infections. Critically ill COVID-19 and influenza patients require extracorporeal membrane oxygenation (ECMO) in cases with severe acute respiratory distress syndrome and have risk factors for invasive pulmonary aspergillosis. Little is known about isavuconazole plasma concentrations during ECMO. OBJECTIVES: To determine isavuconazole plasma concentrations in seven patients treated with intravenous isavuconazole under ECMO and the influence of the ECMO circuit immediately after the first isavuconazole dose. METHODS: Critically ill patients treated with isavuconazole (standard doses) and ECMO were included in this study. Sixty-four blood samples used for measurement of isavuconazole concentrations were collected at several timepoints starting 2 h after the first isavuconazole dose up to 168 h. An additional 27 blood samples were drawn from the inflow and outflow line of the membrane oxygenator to assess any potential isavuconazole clearance effect of the ECMO oxygenation device and the lines. RESULTS: Median isavuconazole trough levels above 1 µg/mL (min. 0.83, max. 1.73) or 2 µg/mL (min. 0.84, max. 2.97) were achieved 24 h or 96 h after the first dose of isavuconazole. The isavuconazole plasma concentrations pre (inflow line) and post (outflow line) the membrane oxygenator were directly correlated (ρ = 0.987, R2 = 0.994, P < 0.001). Post membrane oxygenator isavuconazole concentrations were directly correlated to contemporaneous samples obtained from the arterial lines of patients (ρ = 0.942, R2 = 0.945, P < 0.001). CONCLUSIONS: Isavuconazole concentrations might be influenced by the higher volume of distribution due to ECMO therapy, but were not altered by the ECMO oxygenator and achieved median plasma concentrations >1 µg/mL 24 h after the first loading dose.

Sensitivity and specificity of the antigen-based anterior nasal self-testing programme for detecting SARS-CoV-2 infection in schools, Austria, March 2021.

This study evaluates the performance of the antigen-based anterior nasal screening programme implemented in all Austrian schools to detect SARS-CoV-2 infections. We combined nationwide antigen-based screening data obtained in March 2021 from 5,370 schools (Grade 1-8) with an RT-qPCR-based prospective cohort study comprising a representative sample of 244 schools. Considering a range of assumptions, only a subset of infected individuals are detected with the programme (low to moderate sensitivity) and non-infected individuals mainly tested negative (very high specificity).

Low Rate of SARS-CoV-2 Infections in Symptomatic Patients Attending a Pediatric Emergency Department.

Children and adolescents seem to be at lower risk of developing clinical symptoms of COVID-19. We analyzed the rate of SARS-CoV-2 infections among 3,605 symptomatic children and adolescents at 4,402 outpatient visits presenting to a pediatric emergency department. In a total of 1,105 (32.6%) episodes, the patients fulfilled clinical case definitions for SARS-CoV-2 infection and were tested by nucleic acid testing. A SARS-CoV-2 infection was diagnosed in 10/1,100 episodes (0.3% of analyzed episodes, 0.91% of validly tested patients). Symptoms at presentation did not differ between patients with and without SARS-CoV-2 infection, apart from the frequency of measured temperature ≥37.5°C at presentation. Three percent of analyzed children reported disturbances of olfactory or gustatory senses, but none of them was infected with SARS-CoV-2. The rate of SARS-CoV-2 infections among symptomatic children and adolescents was low and SARS-CoV-2 infections could not reliably be differentiated from other infections without nucleic acid testing.

Autopsy Proven Pulmonary Mucormycosis Due to Rhizopus microsporus in a Critically Ill COVID-19 Patient with Underlying Hematological Malignancy.

Viral infections can cause acute respiratory distress syndrome (ARDS), consequently leading to susceptibility for secondary pulmonary infections. Over the past few weeks, a number of studies have reported on secondary pulmonary aspergillosis complicating severe COVID-19. We report the case of a 53-year old male patient with secondary acute myeloid leukemia (AML) who suffered from COVID-19 ARDS and was diagnosed postmortem with mucormycosis.