Abstract
Objective: To compare the inference regarding the effectiveness of the various non-pharmaceutical interventions (NPIs) for COVID-19 obtained from different SIR models. Study design and setting: We explored two models developed by Imperial College that considered only NPIs without accounting for mobility (model 1) or only mobility (model 2), and a model accounting for the combination of mobility and NPIs (model 3). Imperial College applied models 1 and 2 to 11 European countries and to the USA, respectively. We applied these models to 14 European countries (original 11 plus another 3), over two different time horizons. Results: While model 1 found that lockdown was the most effective measure in the original 11 countries, model 2 showed that lockdown had little or no benefit as it was typically introduced at a point when the time-varying reproduction number was already very low. Model 3 found that the simple banning of public events was beneficial, while lockdown had no consistent impact. Based on Bayesian metrics, model 2 was better supported by the data than either model 1 or model 3 for both time horizons. Conclusion: Inferences on effects of NPIs are non-robust and highly sensitive to model specification. In the SIR modeling framework, the impacts of lockdown are uncertain and highly model-dependent.
Original language | English (US) |
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Pages (from-to) | 96-132 |
Number of pages | 37 |
Journal | Journal of Clinical Epidemiology |
Volume | 136 |
DOIs | |
State | Published - Aug 2021 |
Funding
We congratulate the Imperial College Response Team for sharing openly the code for their models and for the overall transparency of their work that has allowed performing these analyses. We thank Hadi Ashfar for his suggestions to improve the computational efficiency of the HMC scheme. We also thank Jack Wood for his help in the construction of Table A.3. We especially thank the three reviewers and the Editor for their highly thoughtful and deep comments which greatly improved the quality of this paper. We acknowledge the Sydney Informatics Hub and the University of Sydney's high performance computing cluster Artemis for providing the high performance computing resources that have contributed to the research results reported within this paper. Funding: None.
Keywords
- Bayesian statistics
- COVID-19
- Information criteria
- Model comparison
- Non-pharmaceutical interventions
- SIR models
ASJC Scopus subject areas
- Epidemiology