ABSTRACT
Intro Neutralizing antibody responses, including the omicron and other variants targeting SARS-CoV-2, are important serological parameter that may predict protective immunity for COVI-19. This protection status may have a direct impact on the response to this virus including vaccination and protection strategies. Methods The ImTracker Assay™ developed by the National University of Singapore and Gen-Y Biologics is designed to detect and quantify the inhibition of Spike-RBD binding to ACE-2 as a surrogate for SARS-CoV-2 VOC neutralization. Human antibodies that bind to neutralization determinants on Spike-RBDs will block or occlude binding of these viral proteins to the human host receptor, ACE-2. The binding activity of ACE-2 to Spike-RBD in a test sample is compared with negative control sera (minus neutralizing antibodies) where unrestricted binding between the two receptors is not inhibited and a QC reagent (positive control) where binding between Spike-RBD to ACE-2 is inhibited by a defined VOC crossneutralizing agent. A Lateral Flow Immunoassay (LFI), using saliva as a sample, has been developed to detect both mucosal IgG and IgA antibodies. The assays utilized RBD and Nucleocapsid antigens. Findings The assay has been evaluated against all variants including Omicron B.1.1.529 and BA.2 and more recently BA.4 and BA.5. The Assay successfully evaluated over 3,800 positive and 1,300 negative samples utilizing the pseudovirus neutralization test (PVNT) as a reference assay, calibrating this with the WHO international standard for anti-SARS-CoV-2 immunoglobulin. Conclusion ImTracker Assay™ had an overall Sensitivity of 100% and a specificity >96% when benchmarked against a standard PVNT assay. The assay can add additional new variants in less than 45 days. The LFI Immune status provided correlation to vaccination status and when compared to a standard ELISA assay and PVNT neutralizaton assay,provided comparable results.
ABSTRACT
Objective: This is the first prospective cohort study in Singapore to investigate the COVID-19 vaccine-associated myocarditis to understand its pathophysiology. Introduction: Acute myocarditis and other cardiovascular symptoms have been observed to be associated with the two mRNA-based coronavirus disease 2019 (COVID-19) vaccines-namely Pfizer-BioNTech BNT162b2 and Moderna mRNA-1273)-currently in-use in Singapore. The mechanisms through which myocarditis occurs are unknown, hence our study aims to understand the pathophysiology of myocarditis associated with COVID-19 vaccines. Method(s): Patients with onset of cardiac manifestations were recruited from multiple hospital outpatient clinics between November 2021 and September 2022. Clinical history and physical examination data was collected with blood sample collection, echocardiography, 12-lead electrocardiogram (ECG), coronary angiography and magnetic resonance imaging (MRI) at recruitment and 6-month follow-up. Analysis of biomarkers, genetic, serological and MRI data was conducted. Result(s): As of 6 September 2022, a total of 5 patients have been enrolled (4 males, 1 female). The most commonly reported symptoms across all patients were chest pain/discomfort (80%), followed by palpitations (40%). MRI evidence of myocarditis has been detected in 2 (50%) of the male patients, of which both reported two or more symptoms occurring 1-2 days post-vaccination. Both patients have each received at least two doses of either the Pfizer-BioNTech BNT162b2 vaccine or Moderna mRNA-1273 vaccine. Their MRI findings were consistent with myocarditis. On late gadolinium enhancement (LGE) imaging, epicardial enhancement at the basal inferolateral segment and mid-wall enhancement at the apical anterior, lateral and inferior walls were observed in one patient. Patchy, mid-wall LGE in the basal inferior/inferolateral wall was observed in the other patient. No MRI evidence of myocarditis was available for the sole female patient. Conclusion(s): While more data is needed to definitively prove the association of the two mRNA-based Pfizer-BioNTech BNT162b2 and Moderna mRNA-1273 COVID-19 vaccines with post-vaccination myocarditis, we believe our findings may support further investigations to enable risk stratification for vaccine-associated myocarditis and identify potential preventative strategies accordingly.
ABSTRACT
Despite being a convenient clinical substrate for biomonitoring, saliva's widespread utilization has not yet been realized. The non-Newtonian, heterogenous, and highly viscous nature of saliva complicate the development of automated fluid handling processes that are vital for accurate diagnoses. Furthermore, conventional saliva processing methods are resource and/or time intensive precluding certain testing capabilities, with these challenges aggravated during a pandemic. The conventional approaches may also alter analyte structure, reducing application opportunities in point-of-care diagnostics. To overcome these challenges, we introduce the SHEAR saliva collection device that mechanically processes saliva, in a rapid and resource-efficient way. We demonstrate the device's impact on reducing saliva's viscosity, improving sample's uniformity, and increasing diagnostic performance of a COVID-19 rapid antigen test. Additionally, a formal user experience study revealed generally positive comments. SHEAR saliva collection device may support realization of the saliva's potential, particularly in large-scale and/or resource-limited settings for global and community diagnostics. Copyright © 2023 The Authors. Bioengineering & Translational Medicine published by Wiley Periodicals LLC on behalf of American Institute of Chemical Engineers.