Persistence of the Omicron variant of SARS-CoV-2 in Australia: The impact of fluctuating social distancing

PLOS Glob Public Health. 2023 Apr 17;3(4):e0001427. doi: 10.1371/journal.pgph.0001427. eCollection 2023.


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.

Grant support

This work was supported by the Australian Research Council grant DP220101688 (MP, VS, TCS, SLC and QDN). AM is salary funded by an NHMRC Investigator Grant. AMTraC-19 is registered under The University of Sydney’s invention disclosure CDIP Ref. 2020-018. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.