Accelerating SARS-CoV-2 Translational Research Workflows for Molecular Diagnostics, Immune Monitoring and Host Response

The emergence of SARS-CoV-2 created a global crisis, prompting unprecedented efforts by the scientific and medical communities to develop and roll-out diagnostic assays, therapeutics, and vaccines. These efforts significantly reduced viral transmission and saved lives. In 2020, rapid RT-qPCR diagnosis of SARS-CoV-2 became fundamental for pandemic control. However, global demand for testing threatened the testing capacity of Irish hospitals. To address this, we developed a viral RNA extraction workflow with medium-to-high throughput capacity, high reproducibility, and high sensitivity and specificity compared to commercial platforms. This Viral RNA Extraction Kit (VREK) was ready to supply to local hospitals if needed. Quantifying neutralising capacity of circulating SARS-CoV-2 antibodies is essential for evaluating protective immune responses generated post-infection and post-vaccination. We developed a novel medium-throughput flow cytometry-based micro-neutralisation test (Micro-NT) to evaluate neutralisation titres (NT50) against live SARS-CoV-2 Wild Type and Variants of Concern (VOC) in convalescent or vaccinated populations. Micro-NT achieves results comparable to traditional Plaque eduction Neutralisation Test (PRNT) but in less time, and with higher throughput. Using Micro-NT, we quantified NAbs from sera following COVID-19 vaccination and/or infection. We found a strong correlation between NT50 and antibody titres against the SARS-CoV-2 Spike protein, specifically the Receptor Binding Domain (RBD). An IgG titre of 456BAU/ml predicted neutralisation capacity against WT SARS-CoV-2 and Omicron BA.5 in in two diverse cohorts, providing a discrete threshold for identifying individuals at risk of developing severe COVID-19. NT50 serves as a correlate of protection against SARS-CoV-2 infection and severe disease, useful in COVID-19 vaccine trials. COVACC is a European Phase 3 clinical trial assessing reduced COVID-19 mRNA vaccination regimens in paediatric subjects with prior infection. Evaluating NT50s against WT SARS-CoV-2, Omicron BA.5 and Omicron JN.1, we concluded that a one-dose regimen was non-inferior to a two dose regimen in developing functional antibodies against these variants.