Validation of Serological Methods for COVID-19 and Retrospective Screening of Health Employees and Visitors to the São Paulo University Hospital, Brazil.

Reliable serological tests for the detection of SARS-CoV-2 antibodies among infected or vaccinated individuals are important for epidemiological and clinical studies. Low-cost approaches easily adaptable to high throughput screenings, such as Enzyme-Linked Immunosorbent Assays (ELISA) or electrochemiluminescence immunoassay (ECLIA), can be readily validated using different SARS-CoV-2 antigens. A total of 1,119 serum samples collected between March and July of 2020 from health employees and visitors to the University Hospital at the University of São Paulo were screened with the Elecsys® Anti-SARS-CoV-2 immunoassay (Elecsys) (Roche Diagnostics) and three in-house ELISAs that are based on different antigens: the Nucleoprotein (N-ELISA), the Receptor Binding Domain (RBD-ELISA), and a portion of the S1 protein (ΔS1-ELISA). Virus neutralization test (CPE-VNT) was used as the gold standard to validate the serological assays. We observed high sensitivity and specificity values with the Elecsys (96.92% and 98.78%, respectively) and N-ELISA (93.94% and 94.40%, respectively), compared with RBD-ELISA (90.91% sensitivity and 88.80% specificity) and the ΔS1-ELISA (77.27% sensitivity and 76% specificity). The Elecsys® proved to be a reliable SARS-CoV-2 serological test. Similarly, the recombinant SARS-CoV-2 N protein displayed good performance in the ELISA tests. The availability of reliable diagnostic tests is critical for the precise determination of infection rates, particularly in countries with high SARS-CoV-2 infection rates, such as Brazil. Collectively, our results indicate that the development and validation of new serological tests based on recombinant proteins may provide new alternatives for the SARS-CoV-2 diagnostic market.

Characteristics of patients with acute ischemic stroke and covid-19 who required intensive care unit admission versus ward-only: The mississippi academic center experience

Background: Coronavirus disease 2019 (COVID-19) is a viral disease that has primarily been known to cause respiratory symptoms;however, there has also been an association of COVID-19 with neurological symptoms, including acute ischemic stroke (AIS). There is a lack of data on the characteristics of AIS patients with COVID-19 from the stroke belt. We aim to describe the characteristics of patients with COVID-19 and AIS and compare the characteristics of those who required intensive care unit (ICU) admission versus ward-only. Methods: Single center, retrospective cohort study of adult patients admitted in a tertiary academic center from March 1-December 31, 2020. The institutional COVID database was utilized for data collection. Demographic, clinical and laboratory data were collected. Primary outcome measure was mortality. Secondary outcomes included hospital length of stay (LOS) and discharge disposition. Results: Both COVID-19 and AIS were found in 2.4% (n=75) of patients out of 3,031 patients with COVID-19, during the study period. These patients were male (45, 60%), African American (43, 57%), 65±12 years old, with hypertension (69, 92%) and Diabetes Mellitus type 2 (50, 67%). We noted a 20% (n=15) overall in-patient mortality rate among patients with both COVID-19 and AIS. Among these patients, 23% (n=17) required ICU admission. Demographic, clinical and laboratory characteristics were comparable among ICU versus ward-only patients except for higher LDH (476.12±189.70 vs 276.17±88.35 U/L, p==0.0003);and lower relative lymphocytic count (3.57±3.56 vs 8.93±7.83 10 cells/μL, p=0.0160) among those admitted into the ICU. Mortality (13, 68% vs 6, 32%, p<0.001) was significantly higher among the ICU cohort while majority of the ward-only cohort were discharged home (21, 95%). Conclusion: We present the first description of characteristics and outcomes of patients with AIS and COVID-19 from Mississippi. Novel to this cohort is the comparison of those who were admitted into the ICU versus ward-only. Prospective studies analyzing larger datasets of COVID-19 and stroke in the stroke-belt are warranted to further study disparities of care and outcomes.

Inhibition of Severe Acute Respiratory Syndrome Coronavirus 2 Replication by Hypertonic Saline Solution in Lung and Kidney Epithelial Cells.

An unprecedented global health crisis has been caused by a new virus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We performed experiments to test if a hypertonic saline solution was capable of inhibiting virus replication. Our data show that 1.2% NaCl inhibited virus replication by 90%, achieving 100% of inhibition at 1.5% in the nonhuman primate kidney cell line Vero, and 1.1% of NaCl was sufficient to inhibit the virus replication by 88% in human epithelial lung cell line Calu-3. Furthermore, our results indicate that the inhibition is due to an intracellular mechanism and not to the dissociation of the spike SARS-CoV-2 protein and its human receptor. NaCl depolarizes the plasma membrane causing a low energy state (high ADP/ATP concentration ratio) without impairing mitochondrial function, supposedly associated with the inhibition of the SARS-CoV-2 life cycle. Membrane depolarization and intracellular energy deprivation are possible mechanisms by which the hypertonic saline solution efficiently prevents virus replication in vitro assays.