RESUMO
During the SARS-CoV-2 pandemic, multiple variants with differing amounts of escape from pre-existing immunity have emerged, causing concerns about continued protection. Here, we use antigenic cartography to quantify and visualize the antigenic relationships among 16 SARS-CoV-2 variants titrated against serum samples taken post-vaccination and post-infection with seven different variants. We find major antigenic differences caused by substitutions at spike positions 417, 452, 484, and possibly 501. B.1.1.529 (Omicron BA.1) showed the highest escape from all sera tested. Visualization of serological responses as antibody landscapes shows how reactivity clusters in different regions of antigenic space. We find changes in immunodominance of different spike regions depending on the variant an individual was exposed to, with implications for variant risk assessment and vaccine strain selection. One sentence summaryAntigenic Cartography of SARS-CoV-2 variants reveals amino acid substitutions governing immune escape and immunodominance patterns.
RESUMO
Comprehensive and timely testing is required for SARS-CoV-2 variant of concern (VoC) screening. Whole genome sequencing (WGS) provides the broadest means to detect circulating VoCs, but requires longer turnaround time than targeted molecular testing by quantitative polymerase chain reaction (qPCR). We demonstrated the feasibility of a combined testing approach for VoC prevalence assessment in British Columbia, and showed high concordance between qPCR testing and WGS. This directly informed wider VoC screening strategy implementation, and public health efforts.
RESUMO
The COVID-19 pandemic has highlighted the need for generic reagents and flexible systems in diagnostic testing. Magnetic bead-based nucleic acid extraction protocols using 96-well plates on open liquid handlers are readily amenable to meet this need. Here, one such approach is rigorously optimized to minimize cross-well contamination while maintaining sensitivity. Article SummaryA scalable, non-proprietary, magnetic bead-based automated nucleic acid extraction protocol optimised for minimum cross-well contamination
