Significant relaxation of SARS-CoV-2-targeted non-pharmaceutical interventions may result in profound mortality: A New York state modelling study - PubMed (original) (raw)

Significant relaxation of SARS-CoV-2-targeted non-pharmaceutical interventions may result in profound mortality: A New York state modelling study

Benjamin U Hoffman. PLoS One. 2020.

Abstract

Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is the most significant global health crisis of the 21st century. The aim of this study was to develop a model to simulate the effect of undocumented infections, seasonal infectivity, immunity, and non-pharmaceutical interventions (NPIs) on the transmission, morbidity, and mortality of SARS-CoV-2 in New York State (NYS) based on data collected between March 4 and April 28, 2020. Simulations predict that undocumented infections significantly contribute to infectivity, NPIs are effective in reducing morbidity and mortality, and relaxation >50% of NPIs from initial lock-down levels may result in tens-of-thousands more deaths. Endemic infection is likely to occur in the absence of sustained immunity. As a result, until an effective vaccine or other effective pharmaceutical intervention is developed, the risks of significantly reducing NPIs should be carefully considered. This study employs modelling to simulate fundamental characteristics of SARS-CoV-2 transmission, which can help policymakers navigate combating this virus in the coming years.

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Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1

Fig 1. Simulating the effect of undocumented infections on SARS-CoV-2 transmission.

(A-F). Simulation of SARS-CoV-2 transmission dynamics through September 1, 2020. NPIs signified as in (A) top: pink, NPIs initiated on March 22nd, 2020. Orange circles, NYS SARS-CoV-2 data (see Methods). Blue line, simulated projection. Light blue box, 95% confidence interval. A. Cumulative total infections (undocumented infections + confirmed symptomatic infections). B. Cumulative undocumented infections. C. Cumulative confirmed symptomatic infections. D. Active confirmed infections. E. Cumulative hospitalizations. F. Cumulative deaths. See also, S2–S6 Figs, S3 Table.

Fig 2

Fig 2. Reduction of NPIs by >50% may result increased transmission and significant mortality.

(A-F). Simulation of SARS-CoV-2 transmission dynamics in the presence of NPIs through September 1, 2020. Periods of NPIs signified as in (A) top: pink, increased NPIs; green, relaxed NPIs. Orange circles, NYS SARS-CoV-2 data. Lines, simulated projection of reduced NPIs starting June 1, 2020 (yellow, 50% reduction; red, 30% reduction; blue, 15% reduction). A. Active confirmed infections. B. Active hospitalizations. C. Cumulative deaths. D. Heatmap displaying the effect of NPI magnitude and date of reduction on the number of cumulative deaths. E. R(t). F. Categorical heatmap displaying the effect of NPI magnitude and date of reduction on R(t) > 1 (yellow, R(t) > 1; blue R(t) < 1). (G-H). Simulation of extreme reduction of NPIs on June 1, 2020 (yellow, 75%; blue, 25%). G. Active hospitalizations. H. Cumulative deaths. See also, S7 and S8 Figs, S4 Table.

Fig 3

Fig 3. Recurrent outbreak of SARS-CoV-2 in NYS in early 2021.

(A-F). Simulation of SARS-CoV-2 transmission dynamics in the presence of NPIs through September 1, 2021. Simulation assumes 50% NPI reduction on June 1, 2020. Periods of NPIs signified as in (A) top: pink, increased NPIs; green, relaxed NPIs. Orange circles, NYS SARS-CoV-2 data. Lines, simulated projection with resumption of NPIs on December 1, 2020 to Feb 28, 2021, and relaxation after March 1, 2020. A. Active confirmed infections. B. Active hospitalizations. C. Cumulative deaths. D. Heatmap displaying the effect of NPI magnitude and date of resumption on the number of cumulative deaths. E. R(t). F. Categorical heatmap displaying the effect of NPI magnitude and date of resumption on R(t) > 1 (yellow, R(t) > 1; blue R(t) < 1). See also, S9 Fig.

Fig 4

Fig 4. Simulation of sustained immunity to SARS-CoV-2 predicts endemic potential.

(A-D). Simulation of SARS-CoV-2 transmission dynamics in the presence of NPIs through September 1, 2030. The following NPI parameters were assumed: 50% from June 1 to October 31, 2020; 75% from November 1, 2020 to March 1, 2021; 50% after March 1, 2021. Periods of NPIs signified as in (A) top: pink, increased NPIs; green, relaxed NPIs. (A-B). Simulation varying the % of individuals who develop immunity and the average duration of immunity. A. Active confirmed infections. B. Cumulative deaths. C. Heatmap displaying the effect of immunity parameters on cumulative deaths through September 1, 2025. D. Heatmap displaying the effect of immunity parameters on endemic potential. Endemic potential defined as the presence annual recurrence (average total annual infections > 20,000) from September 1, 2023–2025. See also, S10 Fig.

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