We modelled emergence and spread of the Omicron variant of SARS-CoV-2 in Australia between December 2021 and June 2022. This pandemic stage exhibited a diverse epidemiological profile with emergence of co-circulating sub-lineages of Omicron, further complicated by differences in social distancing behaviour which varied over time. Our study delineated distinct phases of the Omicron-associated pandemic stage, and retrospectively quantified the adoption of social distancing measures, fluctuating over different time periods in response to the observable incidence dynamics. We also modelled the corresponding disease burden, in terms of hospitalisations, intensive care unit occupancy, and mortality. Supported by good agreement between simulated and actual health data, our study revealed that the nonlinear dynamics observed in the daily incidence and disease burden were determined not only by introduction of sub-lineages of Omicron, but also by the fluctuating adoption of social distancing measures. Our high-resolution model can be used in design and evaluation of public health interventions during future crises.

翻译：我们模拟了2021年12月至2022年6月期间SARS-CoV-2奥密克戎变异株在澳大利亚的出现和传播。这一大流行阶段呈现出多样化的流行病学特征，伴随奥密克戎共循环亚谱系的出现，且因随时间变化的社交距离行为差异而进一步复杂化。我们的研究明确了奥密克戎相关大流行阶段的各个时期，并回顾性地量化了社交距离措施的采用情况——这些措施在不同时间段内随可观测的发病率动态而波动。我们还模拟了相应的疾病负担，包括住院人数、重症监护病房占用率及死亡率。在模拟数据与实际健康数据高度吻合的支持下，我们的研究揭示：每日发病率及疾病负担中观察到的非线性动态不仅由奥密克戎亚谱系的引入决定，还受社交距离措施采纳程度的波动影响。我们的高分辨率模型可用于未来危机期间公共卫生干预措施的设计与评估。