Long-term outcome of patients with vaccine-induced immune thrombotic thrombocytopenia and cerebral venous sinus thrombosis

Introduction In early 2021, unanticipated thromboses, including cerebral venous sinus thrombosis (CVST) with thrombocytopenia, emerged as an adverse reaction (ADR) in patients who had been vaccinated with the AstraZeneca ChAdOx1 nCoV-19 vaccine. This ADR was termed vaccine-induced immune thrombotic thrombocytopenia (VITT) or thrombosis with thrombocytopenia syndrome (TTS). Although sporadic in nature, VITT can result in severe disease in the individual vaccinee. We followed up on the outcomes and status of neurological recovery of 49 cases of VITT with CVST that were reported to PEI. Method Assessment of the Extended Glasgow Outcome Scale (GOS-E) was performed within 3-6 months after the initial hospital admissions. Individual Glasgow Coma Scale (GCS) scores were reported by phone or electronically via a questionnaire or medical report by the treating physician of the hospital to which the patient was initially admitted. If a GCS score was not reported, an expert determined a score based on the patient's medical report. For most patients, follow-up was pursued about 3-6 months after hospital admission. The reported outcomes describe the patients' neurological status at 5-38 weeks (mean 20 weeks) after hospital admission. Outcomes were identified in 44 of the original 49 cases. Results Patient outcomes ranged from good recovery (13 patients, 29.6 %) to moderate disability (11 patients, 25.0 %) and severe disability or vegetative state (6 patients, 13.6 %). Fatal outcomes were reported in 14 patients (31.8 %). As anticipated, initial low GCS scores were associated with poor outcomes. By contrast, GCS scores > 10 were typically associated with improved neurological outcomes. Moreover, platelet count nadirs were correlated with patient outcomes. Low platelet counts were observed in fatal cases (GOS-E 1) with a mean count of 17,000 platelets/muL). Likewise, patients with better neurological outcomes (GOS-E scores of 5-6 and 7-8) presented with mean counts of 61,000 thrombocytes/muL. However, the course of the disease was not always predictable and showed significant individual variability. Conclusion We provide data on the outcome of VITT cases with CVST upon vaccination with the AstraZeneca adenoviral vector ChAdOx1 nCoV-19 COVID- 19 vaccine and found that the recovery of patients from CVST was very heterogeneous. While some patients exhibited good recoveries, others developed severe disabilities and major long-term complications. Collectively, our findings highlight the importance of paying attention to early signs of increased intracranial pressure and the onset of thrombocytopenia in patients with a recent history of vaccination with the AstraZeneca adenoviral vector ChAdOx1 nCoV-19 COVID-19 vaccine.

Post-Pandemic Intended Use of Remote Teaching and Digital Learning Media in Higher Education. Insights from a Europe-wide Online Survey

The COVID-19 pandemic has had a transformational and potentially long-lasting impact on higher education institutions, with the rapid shift to "Emergency Remote Education”. Two years after the begin of the pandemic, institutions are either returning to presence formats with different speed or converging towards hybrid formats, begging the question what remains of the newly acquired skills and experience with remote teaching and digital learning media? Here, we present the findings of the first European-Union-wide survey on the potential long-term impacts of COVID-19 on higher education, evaluating over 800 responses from students and faculty members of higher education institutions located in 17 different European countries. Our survey - developed in the context of the ide3a university alliance (http://ide3a.net/) highlights possible differences between students and instructors in their attitude toward retaining digital teaching formats and media, examines which formats have increased in use over the course of the pandemic, and investigates which of them are intended to be kept and consolidated post-pandemic. The tools and formats examined in this survey include tools for communication and collaboration, formats of didactic activity, as well as assessment formats. Survey responses reveal that all evaluated tools and format have significantly increased in use during the pandemic and most of them are intended to be used at lower frequency in the future, while still at significantly higher frequency than before the pandemic. Moreover, attitudes toward long-term use of remote teaching and digital learning media seems to be comparable between students and faculty members, except regarding some tools. © 2022 SEFI 2022 - 50th Annual Conference of the European Society for Engineering Education, Proceedings. All rights reserved.

MDW IN COVID-19

BACKGROUND: Sepsis is a major cause of mortality in hospitalization, and better recognition could lead to improved prognosis in critically-ill patients. This study evaluated the use of monocyte distribution width (MDW) to diagnose and predict the prognosis of patients with sepsis in the setting of Covid-19 infections. METHODS: This is a retrospective, observational, single-center cohort study of adult patients with confirmed COVID-19 requiring hospital admission over a 14 month period. MDW was evaluated as a biomarker to predict disease severity, determination of sepsis, and prediction of inpatient mortality. Additionally, it was compared to existing inflammatory markers including ferritin, d-dimer, and procalcitonin. RESULTS: Average MDW was found to be significantly higher in the detection of sepsis (25.50 ± 5.93) vs. patients without (23.13 ± 4.46). An MDW value of 24.9 was shown to be the best cut-off value in determining fatal outcomes;ROC curve analysis revealed an AUC value of 0.69 (95%CI: 0.55- 0.71) with a sensitivity of 83% and specificity of 71%. A Chi-square test was performed, which detected a significant association between MDW values and clinical outcome of Covid-19 (OR =3.52, 95% CL 1.78-7.11, p <0.001). MDW did not correlate with any of the existing inflammatory markers. CONCLUSIONS: MDW is a novel and reliable biomarker in identifying sepsis in patients with Covid-19 infection. High MDW values are associated with a mortality rate or absolute risk of about 25%. MDW is easily obtained from routine laboratory evaluation in the emergency room and maybe a benefit to clinical practice.

Potential Tiger-to-Human Transmission of SARS-CoV-2 at a Tennessee Zoo: A One Health Approach to Outbreak Investigation

Background. Human-to-feline and airborne transmission among cats of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has been described, though documented feline-to-human transmission has not been reported. In October 2020, all 3 Malayan tigers at a Tennessee AZA accredited zoo were diagnosed with symptomatic SARS-CoV-2 infection. We investigated to determine source and prevent further transmission. Methods. Tiger nasal swab specimens were tested at the National Veterinary Services Laboratories (NVSL). An environmental assessment at the zoo was completed. We interviewed 18 staff who interacted with the tigers during the 2 weeks before animal symptom onset. Confirmed human cases were defined as persons testing positive for SARS-CoV-2 by RT-PCR during September 28-October 29, with tiger interaction during their 14-day incubation period. Interviewed staff had repeat SARSCoV-2 RT-PCR and serum IgG testing on October 29. Tigers and staff testing positive had specimens sent to CDC for genomic sequencing. Tiger sequences were compared phylogenetically with 30 geographically associated human cases collected within 2 weeks of the outbreak and > 200 background sequences from TN. Results. NVSL confirmed SARS-CoV-2 infection in all 3 tigers. Environmental assessment identified fencing between humans and animals allowing airflow and an open outdoor exhibit observation point above the habitat. Confirmed cases were identified in a tiger keeper and veterinary assistant;both developed symptoms after exposure to symptomatic tigers and one sample was genotyped. Staff did not report known contact with ill visitors. All staff were negative for SARS-CoV-2 IgG. The tigers and most temporally and geographically associated cases had genetic sequences in clade 20G and B.1.2. Tiger sequences were 3-6 single nucleotide polymorphisms different from the positive tiger keeper (Figure). Figure. Whole-genome phylogenetic analysis. Whole-genome phylogenetic analysis from a portion of clade 20G showing divergence estimates from SARS-CoV-2 Wuhan-Hu-1 reference genome with sequences from humans living in Tennessee and Malayan tigers sampled during the outbreak investigation in October 2020. Sequence analysis showed 3-6 single nucleotide polymorphisms (SNPs) differences between one human tiger keeper and all three tiger sequences. Differences are indicated by one-step edges (lines) between colored dots (individual SARS-CoV-2 sequenced infections). Numbers indicate unique sequences. Note not all analyzed sequences are shown in this figure. Conclusion. Using a One Health approach, we concluded the index tiger was likely infected via transmission from an ill visitor at an exhibit observation point or unidentified asymptomatic staff. Infection spread to the other 2 tigers and tigerto-human transmission to 2 staff is possible thereafter. The zoo was advised on infection control practices for humans and animals, and no additional cases were identified.

Mild COVID-19 elicits early functional plasmablasts and longterm memory B cells while sustaining neutralizing antibody titers

Aim: Evaluate the kinetics of antibody, plasmablasts (PB) and memory B cells (MBCs) from day 7 up to 8 months following mild COVID-19 Methods: This observational study enrolled 31 RT-PCR confirmed acute mild COVID-19 patients longitudinal followed ups at six visits: 0, +7, +14 +28, +56 and +200 days post onset of symptoms (dpos). Antibodies against S1 domain of the spike and N (nucleocapside) proteins of SARSCoV- 2 were evaluated using ELISA, while neutralization was quantified by a commercially available surrogate (sVNT) assay. Specific PB and MBC were assessed by ELISPOT Results: During mild COVID-19, anti-S1, anti-N as well as neutralizing antibodies were elicited during the first 3 weeks pos, reached a peak between 20-30 dpos and decayed slowly, however 80% of patients had detectable neutralizing antibodies at +200 dpos. S1-specific IgA and IgM PB reached their peak around +14 days while IgG slow increased. All patients developed anti-S1 IgG MBCs by one month that peaked at 49 dpos and remained stable up to 245dpos;anti-N IgG MBCs kinetics was similar but their magnitude was reduced. We next correlated humoral with cellular immune responses and found that anti-S1 IgG and IgA titers at visits +14 and +28 days correlated with plasmablast, while there was a poor correlation between antibody titers and MBCs at visit +56 days that was lost at visit +200 days Conclusion: Mild COVID-19 elicits early and long lasting neutralizing antibodies Antigen-specific PB correlated with early antibody titers, while specific MBCs frequencies were stable and independent of antibody titers up to 245 dpos.

Stroke code time metrics and acute thrombolytic use in bedside versus telemedicine assessed acute stroke patients

Objective: To evaluate stroke code time metrics and frequency of rt-PA administration in emergency department (ED) stroke codes evaluated at bedside versus telemedicine. Background: Telemedicine allows for increased access to acute stroke care. Data must be examined regarding differences in stroke code time metrics and acute thrombolytic use in Hub bedside compared to Spoke telemedicine evaluations to optimize care. Design/Methods: We retrospectively reviewed prospectively collected data from an IRBapproved registry. The sample included consecutive stroke code activations at an academic, Comprehensive Stroke Center evaluated at bedside (BG) compared to aggregate telemedicine sites (TG) from 10/1/2013-6/30/2020. We included all rt-PA treated patients. Providers were the same in both groups. We assessed 1) time from ED arrival to treatment decision, 2) ED arrival to rt-PA administration, and 3) treatment rates between groups. Groups were compared via chi-squared, logistic regression, t-test, and Pairwise Wilcoxon where appropriate. Analyses were unadjusted and adjusted for NIHSS as appropriate. Results: In total, 876 patients received rt-PA. There was no significant difference in patients receiving IV rt-PA only versus IV rt-PA and endovascular therapy between BG and TG (p=0.45). There was no significant difference in time from ED arrival to treatment decision between groups ((xBG 35.0 min vs TG 35.0 min;χBG: 35.3 min vs TG: 37.7 min;p=0.09). There was no significant difference in time from ED arrival to rt-PA administration between groups (xBG 53.0 min vs TG 55.0 min;χBG: 57.2 min vs TG: 58.3 min;p=0.69). There was no difference in rt-PA treatment rates amongst the telemedicine spoke sites (p=0.45). Conclusions: There were no significant differences in stroke code time metrics or rt-PA treatment rates in beside versus telemedicine stroke assessments in this study. Ensuring parity in stroke code evaluation is critical as telemedicine use increases due to the COVID-19 pandemic and its implication on the future of healthcare.

SARS-COV2- infection as a trigger of humoral response against apolipoprotein A-1

Background and Aims: Unravelling autoimmune targets triggered by SARS-CoV-2 infection may provide crucial insights in the physiopathology of the disease and foster the development of potential therapeutic candidate targets and prognostic tools. We want to determine whether SARS-CoV-2 exposure could trigger a humoral response against apolipoprotein A-1 (anti-apoA-1 IgG) through molecular mimicry and assess its relationship to patient prognosis. Methods: Anti-Spike domain 1 (SD1) IgGs, anti-apoA-1 IgGs and against mimic peptides, as well as cytokines were assessed by immunoassays on a case-control (n=101), an intensive care unit (ICU;n=126) with a 28-days follow-up, and a general population cohort (n=663) with available samples in the pre and post-pandemic period. Results: Linear sequence homologies and antibodies cross-reactivity between apoA-1, TLR2, and Spike epitopes were identified. Overall, anti-apoA-1 IgG levels were higher in COVID-19 patients or anti-SARS-CoV-2 seropositive individuals than in healthy donors or anti-SARS-CoV-2 seronegative individuals (p<0.0001). Significant and similar associations were noted between anti-apoA-1, anti-SARS-CoV-2 IgG, cytokines, and lipid profile. In ICU patients, anti-SARS-CoV-2 and anti-apoA-1 seroconversion rates displayed similar 7-days kinetics, reaching 82% for anti-apoA-1 seropositivity. C-statistics (CS) indicated that anti-Spike/TLR2 mimic-peptide IgGs displayed a significant prognostic accuracy for overall mortality at 28 days (CS: 0.64;p=0.02). In the general population, SARS-CoV-2 exposure increased baseline anti-apoA-1 IgG levels. Conclusions: COVID-19 induces a marked humoral response against the major protein of high-density lipoproteins. As a correlate of poorer prognosis in other clinical settings, such autoimmunity signatures may relate to long-term COVID-19 prognosis assessment and warrant further scrutiny in the current COVID-19 pandemic.

The SARS-CoV-2 Nsp3 Unique Domain (SUD) interacts with Guanine quadruplexes and this interaction is a potential antiviral target

The multidomain non-structural protein 3 (Nsp3) is the largest protein encoded by coronavirus (CoV) genomes and several regions of this protein are essential for viral replication. Previously, SARS-CoV Nsp3 has been shown to contain a SARS-Unique Domain (SUD), which can bind Guanine-rich non-canonical nucleic acid structures called G-quadruplexes (G4) and is essential for SARS-CoV replication. In this presentation, we will show that the SARS-CoV-2 Nsp3 protein also contains a SUD domain interacting with G4s. We will present structural models for these interactions that reveal significant differences with the 3D structures of the SARS-CoV SUD/G4 complex. We will show data, obtained by three in vitro assays, characterizing the interactions between the SARSCoV- 2 SUD domain and different DNA and RNA G4s. Interestingly, these interactions can be disrupted by specific ligands of these G4s and some of these molecules can inhibit SARS-CoV-2 replication in human lung epithelial cell lines. Altogether, our results pave the way for further studies on the role of SUD/G4 interactions during SARSCoV- 2 replication and the use of inhibitors of these interactions as potent antiviral agents.

The effect of the COVID-19 pandemic on stroke code time metrics at an academic, comprehensive stroke center

Introduction: The COVID-19 pandemic forced immediate changes to stroke code protocols to maintain safety of patients and providers. We hypothesize that stroke code time metrics were significantly longer in the peri-COVID stroke code activations compared to pre-COVID activations. Methods: We analyzed data from an IRB-approved, prospectively collected stroke registry at a large academic, comprehensive stroke center (CSC). We included all patients that presented as stroke code activations from June 2009-August 2020, excluding spoke telestroke and in-house codes. Pre-COVID was defined as June 1, 2009-March 11, 2020 and peri-COVID March 12, 2020 to August 11, 2020. The pre-pandemic stroke code protocol began June 2009. We assessed The Joint Commission stroke code time metrics between groups. Demographic variables of baseline NIHSS, sex, race/ethnicity, age, smoking, pertinent past medical history, arrival mode, and baseline glucose were assessed. A t-test was used to compare stroke code time metrics in minutes. All analyses were done unadjusted. Results: We assessed 813 pre and 328 peri-COVID stroke code activations. Baseline demographics were significant only for an increased number of Hispanics in the pre-COVID group (22.9% vs 11.1%, p<0.001). Onset to hospital arrival time was significantly longer in the peri-COVID compared to pre-COVID group (244 vs 110 min, p<0.001). Onset to stroke code activation was significantly longer in the peri-COVID compared to pre-COVID group (243.8 vs 116.8 min, p<0.009). Time from arrival to treatment decision was significantly decreased in the peri-COVID group (29.9 vs 39.6 min, p=0.04). Time from arrival to CT scan completed (p=0.37), arrival to treatment administration (p=0.06), and onset to treatment administration (p=0.48) were not significantly different between groups. Conclusion: The COVID-19 pandemic significantly impacted the volume and demographic of stroke patients seeking emergency care. This data supports the trend of patients delaying emergent stroke care. This academic, CSC developed and implemented a COVID-19 stroke code protocol within days of a statewide lockdown. The use of telestroke in this peri-pandemic protocol may have accounted for the significant decrease in time to treatment decision.

Income and Poverty in the COVID-19 Pandemic

This paper addresses the economic impact of the COVID-19 pandemic by providing timely and accurate information on the impact of the current pandemic on income and poverty to inform the targeting of resources to those most affected and assess the success of current efforts. We construct new measures of the income distribution and poverty with a lag of only a few weeks using high-frequency data from the Basic Monthly Current Population Survey (CPS), which collects income information for a large, representative sample of US families. Because the family income data for this project are rarely used, we validate this timely measure of income by comparing historical estimates that rely on these data to estimates from data on income and consumption that have been used much more broadly. Our results indicate that at the start of the pandemic, government policy effectively countered its effects on incomes, leading poverty to fall and low percentiles of income to rise across a range of demographic groups and geographies. Simulations that rely on the detailed CPS data and that closely match total government payments made show that the entire decline in poverty that we find can be accounted for by the rise in government assistance, including unemployment insurance benefits and the Economic Impact Payments. Our simulations further indicate that of those losing employment the vast majority received unemployment insurance,though this was less true early on in the pandemic, and receipt was uneven across the states, with some states not reaching a large share of their out of work residents. Updated results during the pandemic for a subset of the tables in this article can be found at povertymeasurement.org.

Antibody persistence in the first 6 months following SARS-CoV-2 infection among hospital workers: a prospective longitudinal study

OBJECTIVES: To evaluate longitudinally the persistence of humoral immunity for up to 6 months in a cohort of hospital employees with mild coronavirus disease 2019 (COVID-19). METHODS: We measured anti-RBD (receptor binding domain of viral spike protein), anti-N (viral nucleoprotein) and neutralizing antibodies at 1, 3 and 6 months after mostly mild COVID-19 in 200 hospital workers using commercial ELISAs and a surrogate virus neutralization assay. RESULTS: Antibodies specific for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) persisted in all participants for up to 6 months. Anti-RBD geometric mean concentrations (GMCs) progressively increased between months 1 (74.2 U/mL, 95%CI: 62.7-87.8), 3 (103.2 U/mL, 95%CI: 87.9-121.2;p < 0.001), and 6 (123.3 U/mL, 95%CI: 103.4-147.0;p < 0.001) in the whole cohort. Anti-N antibodies were detectable in >97% at all times. Neutralizing antibodies were detectable in 99.5% of participants (195/196) at 6 months post infection. Their GMC progressively decreased between months 1 (20.1 AU/mL, 95%CI: 16.9-24.0), 3 (15.2 AU/mL, 95%CI: 13.2-17.6;p < 0.001) and 6 (9.4 AU/mL, 95%CI: 7.7-11.4;p < 0.001). RBD-ACE2-inhibiting antibody titres and anti-RBD antibody concentrations strongly correlated at each timepoint (all r > 0.86, p < 0.001). Disease severity was associated with higher initial anti-RBD and RBD-ACE2-inhibiting antibody titres, but not with their kinetics. CONCLUSIONS: Neutralizing antibodies persisted at 6 months in almost all participants, indicating more durability than initially feared. Anti-RBD antibodies persisted better and even increased over time, possibly related to the preferential detection of progressively higher-affinity antibodies.

Evaluating the Antimicrobial Properties of Commercial Hand Sanitizers.

Hand sanitizers have been developed as a convenient means to decontaminate an individual's hands of bacterial pathogens in situations in which soap and water are not available. Yet to our knowledge, no study has compared the antibacterial efficacy of a large collection of hand sanitizers. Using zone of growth inhibition and kill curve assays, we assessed the performance of 46 commercially available hand sanitizers that were obtained from national chain big-box stores, gasoline stations, pharmacies, and boutiques for antibacterial activity toward prototypical Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacterial pathogens. Results revealed substantial variability in the efficacy of many sanitizers evaluated. Formulations following World Health Organization-recommended ingredients (80% ethanol or 75% isopropyl alcohol) or those including benzalkonium chloride as the active principal ingredient displayed excellent antibacterial activity, whereas others exhibited modest or poor activity in the assays performed. Results also revealed that E. coli was generally more susceptible to most sanitizers in comparison to S. aureus and that there was significant strain-to-strain variability in hand sanitizer antimicrobial efficacy regardless of the organism evaluated. Further, tests of a subset of hand sanitizers toward severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) revealed no direct correlation between antibacterial and antiviral performance, with all ethyl alcohol formulations performing equally well and displaying improved activity in comparison to benzalkonium chloride-containing sanitizer. Taken together, these results indicate that there is likely to be substantial variability in the antimicrobial performance of commercially available hand sanitizers, particularly toward bacterial pathogens, and a need to evaluate the efficacy of sanitizers under development.IMPORTANCE In response to the coronavirus disease 2019 (COVID-19) pandemic, hand hygiene has taken on a prominent role in efforts to mitigate SARS-CoV-2 transmission and infection, which has led to a radical increase in the number and types of hand sanitizers manufactured to meet public demand. To our knowledge, no studies have evaluated or compared the antimicrobial performance of hand sanitizers that are being produced under COVID-19 emergency authorization. Tests of 46 commercially available hand sanitizers purchased from national chain brick-and-mortar stores revealed considerable variability in their antibacterial performance toward two bacterial pathogens of immediate health care concern, S. aureus and E. coli Expanded testing of a subset of hand sanitizers revealed no direct correlation between antibacterial performance of individual sanitizers and their activity toward SARS-CoV-2. These results indicate that as the pandemic subsides, there will be a need to validate the antimicrobial efficacy of sanitizers being produced.

A snapshot of European neurosurgery December 2019 vs. March 2020: just before and during the Covid-19 pandemic.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or Covid-19), which began as an epidemic in China and spread globally as a pandemic, has necessitated resource management to meet emergency needs of Covid-19 patients and other emergent cases. We have conducted a survey to analyze caseload and measures to adapt indications for a perception of crisis. METHODS: We constructed a questionnaire to survey a snapshot of neurosurgical activity, resources, and indications during 1 week with usual activity in December 2019 and 1 week during SARS-CoV-2 pandemic in March 2020. The questionnaire was sent to 34 neurosurgical departments in Europe; 25 departments returned responses within 5 days. RESULTS: We found unexpectedly large differences in resources and indications already before the pandemic. Differences were also large in how much practice and resources changed during the pandemic. Neurosurgical beds and neuro-intensive care beds were significantly decreased from December 2019 to March 2020. The utilization of resources decreased via less demand for care of brain injuries and subarachnoid hemorrhage, postponing surgery and changed surgical indications as a method of rationing resources. Twenty departments (80%) reduced activity extensively, and the same proportion stated that they were no longer able to provide care according to legitimate medical needs. CONCLUSION: Neurosurgical centers responded swiftly and effectively to a sudden decrease of neurosurgical capacity due to relocation of resources to pandemic care. The pandemic led to rationing of neurosurgical care in 80% of responding centers. We saw a relation between resources before the pandemic and ability to uphold neurosurgical services. The observation of extensive differences of available beds provided an opportunity to show how resources that had been restricted already under normal conditions translated to rationing of care that may not be acceptable to the public of seemingly affluent European countries.

Validation of a commercially available SARS-CoV-2 serological immunoassay.

OBJECTIVES: To validate the diagnostic accuracy of a Euroimmun SARS-CoV-2 IgG and IgA immunoassay for COVID-19. METHODS: In this unmatched (1:2) case-control validation study, we used sera of 181 laboratory-confirmed SARS-CoV-2 cases and 326 controls collected before SARS-CoV-2 emergence. Diagnostic accuracy of the immunoassay was assessed against a whole spike protein-based recombinant immunofluorescence assay (rIFA) by receiver operating characteristic (ROC) analyses. Discrepant cases between ELISA and rIFA were further tested by pseudo-neutralization assay. RESULTS: COVID-19 patients were more likely to be male and older than controls, and 50.3% were hospitalized. ROC curve analyses indicated that IgG and IgA had high diagnostic accuracies with AUCs of 0.990 (95% Confidence Interval [95%CI]: 0.983-0.996) and 0.978 (95%CI: 0.967-0.989), respectively. IgG assays outperformed IgA assays (p=0.01). Taking an assessed 15% inter-assay imprecision into account, an optimized IgG ratio cut-off > 2.5 displayed a 100% specificity (95%CI: 99-100) and a 100% positive predictive value (95%CI: 96-100). A 0.8 cut-off displayed a 94% sensitivity (95%CI: 88-97) and a 97% negative predictive value (95%CI: 95-99). Substituting the upper threshold for the manufacturer's, improved assay performance, leaving 8.9% of IgG ratios indeterminate between 0.8-2.5. CONCLUSIONS: The Euroimmun assay displays a nearly optimal diagnostic accuracy using IgG against SARS-CoV-2 in patient samples, with no obvious gains from IgA serology. The optimized cut-offs are fit for rule-in and rule-out purposes, allowing determination of whether individuals in our study population have been exposed to SARS-CoV-2 or not. IgG serology should however not be considered as a surrogate of protection at this stage.