Quantifying what could have been – The impact of the Australian and New Zealand governments’ response to COVID-19

Highlights

• We discuss the government response in Australia and New Zealand to the COVID-19 global pandemic.

• We quantify and visualise the likely daily cases were it not for the government response.

• A Bayesian structural time series model was used to generate the counterfactual, i.e. the ‘what-if’ scenario.

Abstract

Background

The Australian and New Zealand governments both initiated strict social distancing measures in response to the COVID-19 pandemic in late March. It remains difficult to quantify the impact this had in reducing the spread of the virus.

Methods

Bayesian structural time series model provide a model to quantify the scenario in which these government-level interventions were not placed. Our models predict these strict social distancing measures caused a 79% and 61% reduction in the daily cases of COVID-19 across Australia and New Zealand respectively.

Conclusion

This provides both evidence and impetus for governments considering similar measures in response to COVID-19 and other pandemics.