Optimal Timing and Effectiveness of COVID-19 Outbreak Responses in China: A Modelling Study
50 Pages Posted: 10 Apr 2020 Last revised: 14 Apr 2020
Date Written: March 21, 2020
Background: In January 2020, an outbreak of atypical pneumonia caused by a novel coronavirus, SARS-CoV-2, was reported in Wuhan, China. On Jan 23, 2020, the Chinese government instituted mitigation strategies to control spread. Previous modeling studies have focused on projecting epidemiological outcomes throughout the epidemic in China. However, the impact and optimal timing of different mitigation approaches have not been evaluated.
Methods: We developed a mathematical model reflecting SARS-CoV-2 transmission dynamics. The model simulates health and economic outcomes from Dec 1, 2019, through Mar 31, 2020, for Wuhan, Chongqing, Beijing, and Shanghai, China. We considered differences in timing and duration of three mitigation strategies: city-wide quarantine on Wuhan, travel history screening and isolation of travelers from Wuhan to other Chinese cities, and social distancing.
Findings: Our model predicted that implementing all three mitigation strategies one week earlier would have averted 35% of deaths in Wuhan (50% in other cities) at an increased economic loss of 8% (16-18% in other cities). Delaying mitigation strategies by one week was predicted to decrease economic losses by the same amount, but with 50% more deaths in Wuhan and twice as many deaths in the other cities. Of the three mitigation approaches, infections and deaths increased most rapidly if initiation of social distancing was delayed. Furthermore, the duration of social distancing among adults had the greatest impact on infections and deaths compared to prolonged social distancing among adolescents and the elderly.
Interpretation: Optimizing the timing of epidemic mitigation strategies is paramount and involves weighing tradeoffs between preventing infections and deaths and immense economic impacts. The majority of the benefit of China's mitigation strategy was likely due to social distancing measures, which also incurred a much lower daily cost than a city-wide quarantine. In particular, workplace closures were most beneficial in preventing both infections and deaths rather than differential social distancing among younger or older age groups.
Note: Funding: We did not receive any funding support.
Competing Interest Declaration: The authors declare no competing interests.
Keywords: COVID-19, SARS-CoV-2, quarantine, social distancing, travel history screening, optimal strategy
JEL Classification: I10, I15
Suggested Citation: Suggested Citation