Anzai Asami, Kobayashi Tetsuro, Linton Natalie M, Kinoshita Ryo, Hayashi Katsuma, Suzuki Ayako, Yang Yichi, Jung Sung-Mok, Miyama Takeshi, Akhmetzhanov Andrei R, Nishiura Hiroshi
Graduate School of Medicine, Hokkaido University, Kita 15 Jo Nishi 7 Chome, Kita-ku, Sapporo-shi, Hokkaido 060-8638, Japan.
Osaka Institute of Public Health, Nakamichi 1-3-69, Higashinari, Osaka 537-0025, Japan.
J Clin Med. 2020 Feb 24;9(2):601. doi: 10.3390/jcm9020601.
The impact of the drastic reduction in travel volume within mainland China in January and February 2020 was quantified with respect to reports of novel coronavirus (COVID-19) infections outside China. Data on confirmed cases diagnosed outside China were analyzed using statistical models to estimate the impact of travel reduction on three epidemiological outcome measures: (i) the number of exported cases, (ii) the probability of a major epidemic, and (iii) the time delay to a major epidemic. From 28 January to 7 February 2020, we estimated that 226 exported cases (95% confidence interval: 86,449) were prevented, corresponding to a 70.4% reduction in incidence compared to the counterfactual scenario. The reduced probability of a major epidemic ranged from 7% to 20% in Japan, which resulted in a median time delay to a major epidemic of two days. Depending on the scenario, the estimated delay may be less than one day. As the delay is small, the decision to control travel volume through restrictions on freedom of movement should be balanced between the resulting estimated epidemiological impact and predicted economic fallout.
针对中国境外新型冠状病毒（COVID-19）感染报告，对2020年1月和2月中国大陆境内旅行量急剧减少的影响进行了量化。利用统计模型分析中国境外确诊病例的数据，以估计旅行减少对三项流行病学结果指标的影响：（i）输出病例数，（ii）大流行的概率，以及（iii）大流行的时间延迟。2020年1月28日至2月7日，我们估计预防了226例输出病例（95%置信区间：86,449），与反事实情景相比，发病率降低了70.4%。在日本，大流行概率的降低幅度为7%至20%，这导致大流行的中位时间延迟为两天。根据不同情景，估计延迟可能不到一天。由于延迟较小，通过限制行动自由来控制旅行量的决定应在由此产生的估计流行病学影响和预测的经济影响之间取得平衡。
