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. 2020 Jul:128:104440.
doi: 10.1016/j.jcv.2020.104440. Epub 2020 May 15.

Modeling the effects of intervention strategies on COVID-19 transmission dynamics

Deanna M Kennedy  1 , Gustavo José Zambrano  2 , Yiyu Wang  1 , Osmar Pinto Neto  3
Affiliations

Modeling the effects of intervention strategies on COVID-19 transmission dynamics

Deanna M Kennedy et al. J Clin Virol. 2020 Jul.

Abstract

Objectives: To model the effects of continuous, intermittent, and stepping-down social distancing (SD) strategies and personal protection measures on COVID-19 transmission dynamics.

Methods: Constant, intermittent, and stepping-down SD strategies were modeled at 4 mean magnitudes (5%, 10 %, 15 % and 20 %), 2 time windows (40-days, 80-days), and 2 levels of personal caution (30 % and 50 %).

Results: The stepping-down strategy was the best long-term SD strategy to minimize the peak number of active COVID-19 cases and associated deaths. The stepping-down strategy also resulted in a reduction in total time required to SD over a two-year period by 6.5 % compared to an intermittent or constant SD strategy. An 80-day SD time-window was statistically more effective in maintaining control over the COVID-19 pandemic than a 40-day window. However, the results were dependent upon 50 % of people being cautious (engaging in personal protection measures).

Conclusion: If people exercise caution while in public by protecting themselves (e.g., wearing a facemask, proper hand hygiene and avoid agglomeration) the magnitude and duration of SD necessary to maintain control over the pandemic can be reduced. Our models suggest that the most effective way to reduce SD over a two-year period is a stepping-down approach every 80 days. According to our model, this method would prevent a second peak and the number of intensive care units needed per day would be within the threshold of those currently available.

Keywords: COVID-19; Compartmental model; Intervention strategies; Mathematical modeling; Pandemic.

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Conflict of interest statement

Declaration of Competing Interest The authors declare no conflict of interest.

Figures

Fig. 1
Fig. 1
Fitting results for accumulated cases (a) and deaths (b) for US. And an illustration of the 95 % confidence interval estimated for the ICU beds used per day ICU-PD (c) for one example of scenarios illustrating a “stepping-down” SD strategy (d) with a minimum protection percentage of 50 % (e).
Fig. 2
Fig. 2
Model results for active cases per day (a), total ICU beds per day (b), hospitalizations per day (c), accumulative deaths (d), accumulative cases (e), accumulative recuperated cases (f), as well as SD strategies (g), and protection percentage (h) in USA. Initial stepping down SD starts at 40 %, then it is divided by half for the next 3 windows, and the pattern repeats itself from the start (80 days/window); intermittent SD alternate 40 % and 0; constant strategy keeps SD at 20 % for the total duration of the pandemic. Protection percentage drops from current estimated values of 68 % to either 50 % or 30 %.
Fig. 3
Fig. 3
Model results for active cases per day (a), total ICU beds per day (b), hospitalizations per day (c), accumulative deaths (d), accumulative cases (e), accumulative recuperated cases (f), as well as social distancing (SD) strategies (g), and protection percentage (h) in US. Initial stepping-down SD starts at 30 %, then it is divided by half for the next 3 windows, and the pattern repeats itself from the start (80 days/window); intermittent SD alternate 30 % and 0; constant strategy keeps SD at 15 % for the total duration of the pandemic. Protection percentage drops from current estimated values of 68 % to either 50 % or 30 %.
Fig. 4
Fig. 4
Model results for active cases per day (a), ICU beds per day (b), hospitalizations per day (c), accumulative deaths (d), accumulative cases (e), accumulative recuperated cases (f), as well as social distancing (SD) strategies (g), and protection percentage (h) in US. Initial stepping-down SD starts at 20 %, then it is divided by half for the next 3 windows, and the pattern repeats itself from the start (80 days/window); intermittent SD alternate 20 % and 0; constant strategy keeps SD at 10 % for the total duration of the pandemic. Protection percentage drops from current estimated values of 68 % to either 50 % or 30 %.
Fig. 5
Fig. 5
Model results for active cases per day (a), total ICU beds per day (b), hospitalizations per day (c), accumulative deaths (d), accumulative cases (e), accumulative recuperated cases (f), as well as social distancing (SD) strategies (g), and protection percentage (h) in US. Initial stepping-down SD starts at 10 %, then it is divided by half for the next 3 windows, and the pattern repeats itself from the start (80 days/window); intermittent SD alternate 10 % and 0; constant strategy keeps SD at 5% for the total duration of the pandemic. Protection percentage drops from current estimated values of 68 % to either 50 % or 30 %.
Fig. 6
Fig. 6
Model results for active cases per day (a), total ICU beds per day (b), hospitalizations per day (c), accumulative deaths (d), accumulative cases (e), accumulative recuperated cases (f), as well as social distancing (SD) strategies (g), and protection percentage (h) in US. Initial-stepping down SD starts at 30 %, then it is divided by half for the next 3 windows, and the pattern repeats itself from the start (40 days/window); intermittent SD alternate 30 % and 0; constant strategy keeps SD at 15 % for the total duration of the pandemic. Protection percentage drops from current estimated values of 68 % to either 50 % or 30 %.
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