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The Transmission Dynamics of SARS-COV-2 in China: Modeling Study and the Impact of Public Health Interventions
39 Pages Posted: 17 Mar 2020
More...Abstract
Background: COVID-19 is breaking out and has become a global pandemic. However, at present, the transmission dynamics remain unclear. We aimed to establish a SEIRD mathematical model based on the existing data to fit the transmission curve and evaluate the effects of the existing public health interventions.
Methods: First, the incidence of COVID-19 in the eight provinces to which the highest number of people moved from Wuhan between Jan 14 and Jan 23 was used to estimate the number of infected people in the incubation period in Wuhan city; and then the reproductive number (R0) was calculated by the SEIRD model and differential equations. In addition, the parameters of the SEIRD model were estimated to simulate the transmission trend. Furthermore, the fit of the model was verified. Finally, the infection curve and daily transmission replication curve were constructed, and the trend of cumulative confirmed cases was used to evaluate the effects of the public health interventions.
Findings: In the SEIRD model established in the present study, we estimated that R0 is 3.38 (95% CI, 3.25–3.48). The SEIRD curve model had a good fit when the parameters were set as follows: from Jan 24 to Jan 29, R = 2.37, TE = 6, TI = 3.5, and k = 0 . 0306; from Jan 30 to Feb 4, R = 1.78, TE = 6, TI = 3.5, and k = 0.0306; from Feb 5 to Feb 11, R = 0.83, TE = 6, TI = 3.5, and k = 0.0306, and from Feb 12 to Mar 5, R = 0.5, TE = 6, TI = 3.5, and k = 0.0306. The SEIRD curve from Feb 12 to Mar 5 (including the cumulative number of cases curve, the number of new cases curve, and the cumulative number of deaths curve) show a small difference between the simulated number of cases and the actual number; the correlation index (H2) is 0.934, and the reproductive number (R) has been reduced from 3.38 to 0.5 under the current public health interventions. According to the prediction SEIRD curves of three different states (A, B, and C), the final cumulative number of cases in China is about 70,000–100,000. Finally, the actual growth curve of new cases, the virus infection curve, and the daily transmission replication curve indicate that the public health interventions are effective.
Interpretation: According to the SEIRD model curve we established, the transmission dynamics of SARS-COV-2 far exceed those of SARS in 2003, and the estimated final number of cases in China lies between 70,000 and 100,000. The current public health interventions are effective and should be maintained or strengthened until COVID-19 is no longer considered a global threat.
Funding Statement: Natural Science Foundation of Fujian Province (2019J01312) in China.
Declaration of Interests: None of the authors have any conflicts of interest.
Keywords: COVID-19; SARS-COV-2; SEIRD; Wuhan; Public health interventions; Transmission dynamics
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