Speaker
Description
With the need to assess the potential impact that rapidly emerging variants will have on the population, I have worked with academic and public health (PH) teams in Canada to create and operationalize a set of tools needed for real-time evaluation and explanation of risk to senior officials and to maintain awareness across the country. In this talk, I will discuss key observations from recent waves of variants of concern (VOC) or interest (VOI) waves in Canada, referencing results from measures of variant fitness, wave metrics, nowcasting, phylogenies, phylogeographical inference of introductions, and retrospective variant benchmarks. While many major variant dynamic patterns were observed globally, there were regional differences, especially in Canada, due to its particular geography and federated health system. I will discuss how many of the analytics developed were driven by PH questions specific to phases of the wave dynamics and the (often rapidly) changing PH decision-making processes that follow them. With the emergence of the Omicron phenotype and its descendants, continuous replacement dynamics have settled into approximately 4 major variant replacements per year. In Canada, the waves are seasonally larger in fall, winter, and spring, with a smaller wavelet in summer. Despite high levels of vaccination and natural immunity at a global scale, these replacement-wave dynamics continue to be much faster than other respiratory viruses and the variants continue to demonstrate changes in phenotype and vaccine/treatment escape. Therefore, maintaining some baseline genomic surveillance of COVID-19 that can feed the analytics needed at the different phases of the variant dynamics is warranted. However, the set of evaluation metrics must be adapted to the current/emerging regime of lower sampling rates, immunity conditions, and need to predict future variants. Pushing the state-of-the-art to achieve these goals is driving the advancement of research in viral evolutionary dynamics.
