School of Public Health and Management, Ningxia Medical University, Yinchuan Ningxia, China 750004.
Biomed Res Int. 2020 May 18;2020:3842470. doi: 10.1155/2020/3842470. eCollection 2020.
Recently, a large-scale novel coronavirus pneumonia (NCP) outbreak swept China. As of Feb. 9, 2020, a total of 40,260 patients have been diagnosed with NCP, and 23,589 patients were suspected to have infected by the 2019 novel coronavirus (COVID-19), which puts forward a great challenge for public health and clinical treatment in China. Until now, we are in the high-incidence season of NCP. Thus, the analysis of the transmissibility change of NCP and its potential factors may provide a reliable reference for establishing effective prevention and control strategies.
By means of the method of calculating the instantaneous basic reproduction number proposed by Cori et al. (2013), we use to describe the transmissibility change of COVID-19 in China, 2019-2020. In addition, the Baidu Index (BDI) and Baidu Migration Scale (BMS) were selected to measure the public awareness and the effect of Wuhan lockdown (restricted persons in Wuhan outflow from the epidemic area) strategy, respectively. The Granger causality test (GCT) was carried out to explore the association between public awareness, the effect of the Wuhan lockdown strategy, and the transmissibility of COVID-19.
The estimated averaged basic reproduction number of NCP in China was 3.44 with 95% CI (2.87, 4.0) during Dec. 8, 2019, to Feb. 9, 2020. The instantaneous basic reproduction numbers ( ) have two waves and reaching peaks on Jan. 8 and Jan. 27, respectively. After reaching a peak on Jan. 27, showed a continuous decline trend. On Feb. 9, has fallen to 1.68 (95% CI: 1.66, 1.7), but it is still larger than 1. We find a significantly negative association between public awareness and the transmissibility change of COVID-19, with one unit increase in cumulative BDI leading to a decrease of 0.0295% (95% CI: 0.0077, 0.051) . We also find a significantly negative association between the effect of the Wuhan lockdown strategy and the transmissibility change of COVID-19, and a one unit decrease in BMS may lead to a drop of 2.7% (95% CI: 0.382, 4.97) .
The current prevention and control measures have effectively reduced the transmissibility of COVID-19; however, is still larger than the threshold 1. The results show that the government adopting the Wuhan lockdown strategy plays an important role in restricting the potential infected persons in Wuhan outflow from the epidemic area and avoiding a nationwide spread by quickly controlling the potential infection in Wuhan. Meanwhile, since Jan. 18, 2020, the people successively accessed COVID-19-related information via the Internet, which may help to effectively implement the government's prevention and control strategy and contribute to reducing the transmissibility of NCP. Therefore, ongoing travel restriction and public health awareness remain essential to provide a foundation for controlling the outbreak of COVID-19.
近期，中国发生了大规模的新型冠状病毒肺炎（NCP）疫情。截至 2020 年 2 月 9 日，共诊断出 40260 例 NCP 病例，23589 例疑似感染 2019 年新型冠状病毒（COVID-19），这对中国的公共卫生和临床治疗提出了巨大挑战。截至目前，我们正处于 NCP 的高发季节。因此，分析 NCP 的传染性变化及其潜在因素，可能为制定有效的预防和控制策略提供可靠参考。
采用科里等人（2013 年）提出的瞬时基本繁殖数 的计算方法，用 描述 2019-2020 年中国 COVID-19 的传染性变化。此外，选择百度指数（BDI）和百度迁徙规模（BMS）分别衡量公众意识和武汉封城（限制武汉疫区人员外流）策略的效果。采用格兰杰因果检验（GCT）探讨公众意识、武汉封城策略效果与 COVID-19 传染性之间的关联。
2019 年 12 月 8 日至 2020 年 2 月 9 日，中国 NCP 的估计平均基本繁殖数为 3.44（95%CI：2.87，4.0）。瞬时基本繁殖数（ ）有两个波，分别于 1 月 8 日和 1 月 27 日达到峰值。1 月 27 日达到峰值后， 呈持续下降趋势。2 月 9 日， 已降至 1.68（95%CI：1.66，1.7），但仍大于 1。我们发现公众意识与 COVID-19 传染性变化呈显著负相关，累积 BDI 每增加一个单位， 就会下降 0.0295%（95%CI：0.0077，0.051）。我们还发现武汉封城策略效果与 COVID-19 传染性变化呈显著负相关，BMS 每下降一个单位， 可能下降 2.7%（95%CI：0.382，4.97）。
目前的防控措施已有效降低了 COVID-19 的传染性；然而， 仍大于 1。结果表明，政府采取的武汉封城策略在限制武汉疫区潜在感染者流出疫区、避免全国范围传播方面发挥了重要作用，通过快速控制武汉的潜在感染，迅速控制了疫情。同时，自 2020 年 1 月 18 日以来，人们通过互联网陆续获取了 COVID-19 相关信息，这可能有助于政府有效实施防控策略，有助于降低 NCP 的传染性。因此，持续的旅行限制和公众卫生意识仍然至关重要，为控制 COVID-19 的爆发提供了基础。
