春节全国人口大流动下的新冠肺炎疫情控制
陈思邈，杨俊涛，杨维中，*王辰
thelancet.com
当前，新型冠状病毒引发的肺炎疫情仍在中国持续扩散蔓延。【1】疫情发展初期正值今年春节，这是中国一年中最重要的节日。大量民众集中在春节期间返乡，形成全国大规模的人口流动。春运一般持续40天，在此期间全国客运量约达30亿人次。【2】湖北省会武汉是此次疫情重灾区，500多万人在1月23日封城前就已离城，【3】其中约三分之一流入了外省。【4】减少这些人群的社会接触至关重要，因为无症状或轻微症状的新冠肺炎患者仍具有传染性。【5】
中国政府在春节假期期间实施了一系列增加社会距离(social distancing)的措施，以减少人群间接触次数、增加人群间距离，这使得春节假期对于阻遏疫情蔓延可能起到一定作用。这些举措包括鼓励居家休养，减少群众聚集性活动，取消或推迟大型公共活动，关闭图书馆、博物馆，学校全部停课，部分政府机构停工，工厂停业；部分城市公交车、省际客运停运。【6–10】得益于这一系列政策措施、信息公开和健康宣传教育，广大民众普遍有了自我保护意识，尽量不出门、不集会、不聚餐，减少了人际间的接触，如必须出门亦会采取戴口罩等防护措施。
历史上抗击其它疫情的文献表明，增加社会距离措施能够有效遏制“人传人”的扩散，降低患病率和死亡率。【11–17】虽然单个增加社会距离措施可以产生一定效果，但更通常的做法是与强制隔离等方式相结合，多措并举以增强干预效果。例如，在1918-1919年大流感期间，纽约市同时实施多种隔离措施，包括错峰上班与强制隔离等，这使纽约成为了美国东部沿海地区流感死亡率最低的城市。【17】
各级政府和专家学者担心的是，1月31日春节假期结束后，全国范围内大规模的返工潮所带来的人群流动，极有可能会进一步加剧疫情蔓延。此外，春节后人员返程时间距离假期刚过一周，短于新冠肺炎最长潜伏期。【18】在春节假期结束后，武汉封城前出城的500万人口中，【3】有相当一部分可能还处于潜伏期内，而这类潜在感染者在假期结束后的大规模流动，必将对遏制疫情造成一定的困难。
基于以上考虑，中国政府延长了春节假期。湖北省延至3月10日，【19】其他部分省市延至2月9日，【20–22】以使假期长于病毒最长潜伏期。同时，将新冠肺炎确诊病人在医院进行隔离。在感染人数最多的武汉，轻症确诊患者被隔离在由大型建筑（如体育馆或会议展览中心）迅速转型而来的大规模临时医疗场所，即“方舱医院”。此外，中国政府充分发挥社区动员能力，实施网格化、地毯式排查与管理、追踪管理密切接触者，做到对患者的尽早发现与收治；通过社交媒体进行科普，鼓励公众勤洗手、勤消毒、出门戴口罩。由于实施了延长假期及这些举措，许多由湖北省前往其它省份的无症状感染者在出现症状前已处于隔离状态，出现症状后即接受治疗。对去过疫情重灾区的人群进行居家隔离，可能是遏制病毒在其它省份传播与蔓延的有效举措。
此次延长春节假期可得到的启示有：首先，面临新冠肺炎病毒潜在传播的国家，或是在未来应对新型突发传染病疫情时，可考虑将“控疫假期”或“控疫停工停学期”作为一种增加社会距离的方法来降低疾病传染率。例如，在一段时间内关闭非生活必需的工作场所和公共设施。其次，“控疫假期”时长的确定，应考虑到该新发传染病的流行特征，例如潜伏期和传播途径。第三，“控疫假期”的核心是在整个停工停学期，防止潜伏期无症状感染人群传播疾病。因此，政府应充分利用“控疫假期”进行防控知识的宣传教育，严格执行社区网格化、地毯式排查等措施，及时追踪管理密切接触者，使各项举措的社会效果最大化。研究表明，增加社会距离与其它干预措施的结合使用能更为有效地降低疾病传染率，这为疫情防控多措并举提供了理论支持。【23】
中国在抗击新冠肺炎疫情的过程中，将“控疫假期”与其它措施结合使用，对遏制疫情蔓延起到了一定的作用，这从湖北以外的省份每天新增确诊病例已连续下降两周多可见一斑。1虽然新冠肺炎疫情自暴发以来引起了民众恐慌并造成了巨大的影响，但中国强有力且多措并举的应对方式，有效防止了疫情形势的进一步恶化。对延长春节假期期间的增加社会距离及疫情防控政策的总体效果，还需要在未来的实证研究中进行评估。随着人们逐渐返工，中国应继续执行部分政策来确保新冠肺炎疫情能够被持续控制。
Chen S, Yang J, Yang W, Wang C, Bärnighausen T. COVID-19 control in China during mass population movements at New Year. Lancet 2020; 395: 764–66.doi.org/10.1016/S0140-6736(20)30421-9
参考文献:
1 National Health Commission of the People’s Republic of China. Updates on the epidemic. Feb 19, 2020. http://www.nhc.gov.cn/xcs/yqtb/list_gzbd.shtml (accessed Feb 19, 2020 [in Chinese]).
2 Ministry of Transport of the People’s Republic of China. Big data! The travel volume predictions during Lunar New Year holiday in 2020. Jan 9, 2020. http://www.mot.gov.cn/fenxigongbao/yunlifenxi/202001/t20200109_3322161.html (accessed Feb 15, 2020 [in Chinese]).
3 China News. The press conference on COVID-19 in Hubei. Jan 26, 2020. https://m.chinanews.com/wap/detail/zb/2493.shtml (accessed Feb 19, 2020 [in Chinese]).
4 Baidui Map. Location-based services of Baidu database. Feb 19, 2020. https://qianxi.baidu.com (accessed Feb 19 2020).
5 Guan W-J, Ni Z-Y, Hu Y, et al. Clinical characteristics of 2019 novel coronavirus infection in China. medRxiv 2020: published online Feb 9. https://doi.org/10.1101/2020.02.06.20020974 (preprint).
6 The State Council of the People’s Republic of China. The State Council’s announcement on the arrangement of public holidays in 2020. Nov 21, 2019. http://www.gov.cn/zhengce/content/2019-11/21/content_5454164.htm (accessed Feb 3, 2020 [in Chinese]).
7 The State Council of the People’s Republic of China. The State Council’s announcement on extending the Lunar New Year Holiday in 2020. Jan 27, 2020. http://www.gov.cn/zhengce/content/2020-01/27/content_5472352.htm (accessed Jan 31, 2020 [in Chinese]).
8 National Health Commission of the People’s Republic of China. The press conference on Jan 26, 2020. Jan 26, 2020. http://www.nhc.gov.cn/xcs/fkdt/202001/12ec9062d5d041f38e210e8b69b6d7ef.shtml (accessed Jan 31, 2020 [in Chinese]).
9 The People’s Government of Beijing Municipality. The announcement of cancellations of major events including temple fairs in Beijing. Jan 23, 2020. http://www.beijing.gov.cn/ywdt/gzdt/t1614497.htm (accessed Feb 3, 2020 [in Chinese]).
10 The State Council of the People’s Republic of China. The announcement from Wuhan’s headquarter on the novel coronavirus prevention and control. Jan 23, 2020. http://www.gov.cn/xinwen/2020-01/23/content_5471751.htm (accessed Jan 31, 2020 [in Chinese]).
11 Poletti P, Caprile B, Ajelli M, Pugliese A, Merler S. Spontaneous behavioural changes in response to epidemics. J Theor Biol 2009; 260: 31–40.
12 Hatchett RJ, Mecher CE, Lipsitch M. Public health interventions and epidemic intensity during the 1918 influenza pandemic. Proc Natl Acad Sci USA 2007; 104: 7582–87.
13 Ahmed F, Zviedrite N, Uzicanin A. Effectiveness of workplace social distancing measures in reducing influenza transmission: a systematic review. BMC Pub Health 2018; 18: 518.
14 Ferguson NM, Cummings DA, Cauchemez S, et al. Strategies for containing an emerging influenza pandemic in Southeast Asia. Nature 2005; 437: 209–14.
15 Glass RJ, Glass LM, Beyeler WE, Min HJ. Targeted social distancing designs for pandemic influenza. Emerg Infect Dis 2006; 12: 1671.
16 Caley P, Philp DJ, McCracken K. Quantifying social distancing arising from pandemic influenza. J Roy Soc Interface 2008; 5: 63–69.
17 Markel H, Lipman HB, Navarro JA, et al. Nonpharmaceutical interventions implemented by US cities during the 1918–1919 influenza pandemic. JAMA 2007; 298: 644–54.
18 Li Q, Guan X, Wu P, et al. Early transmission dynamics in Wuhan, China, of novel coronavirus–infected pneumonia. N Engl J Med 2020; published online Jan 29. DOI:10.1056/NEJMoa2001316.
19 The People’s Government of Hubei Province. The announcement from the Hubei Provincial Novel Coronavirus Pneumonia Prevention and Control Headquarter. Feb 20, 2020. http://www.hubei.gov.cn/zhuanti/2020/gzxxgzbd/zxtb/202002/ (accessed Feb 20, 2020 [in Chinese]).
20 The People’s Government of Beijing Municipality. Companies can flexibly arrange jobs during the novel coronavirus epidemic except for those absolutely necessary for the normal operation of cities. Feb 1, 2020. http://www.gov.cn/xinwen/2020-02/01/content_5473522.htm (accessed Feb 3, 2020 [in Chinese]).
21 The People’s Government of Shanghai Municipality. The announcement on postponing the reoperation date of companies and the reopening date of schools. Jan 27, 2020. http://www.shanghai.gov.cn/nw2/nw2314/nw2315/nw43978/u21aw1423601.html (accessed Feb 15, 2020 [in Chinese]).
22 The People’s Government of Hangzhou Municipality. The announcement on postponing the reoperation date of companies and the reopening date of schools. Jan 27, 2020. http://www.hangzhou.gov.cn/art/2020/2/9/art_1256295_41893739.html (accessed Feb 15, 2020 [in Chinese]).
23 Fong M, Gao H, Wong J, et al. Nonpharmaceutical measures for pandemic influenza in nonhealthcare settings—social distancing measures. Emerg Infect Dis 2020; published online Feb 6. DOI:10.3201/eid2605.190995.
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