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：Translated abstract: 本文模拟了2021年12月至2022年6月期间奥密克戎变异体在澳大利亚的出现和传播。这个阶段表现出多样的流行病学特征，包括不同时间出现的共同流行亚型和不断变化的社交疏远行为。本研究划分奥密克戎相关大流行阶段的不同阶段，并回顾性地量化了社交疏远措施的采取情况，这些措施随着可观察到的发病动态在不同的时间段内波动。我们还模拟了相应的疾病负担，包括住院、重症监护室占用和死亡率。得益于模拟数据和实际健康数据之间的良好一致性，我们的研究揭示了每日发病率和疾病负担中观察到的非线性动态不仅取决于奥密克戎亚型的引入，还取决于社交疏远措施的波动采取。我们的高分辨率模型可用于未来危机期间公共卫生干预的设计和评估。