Zhao Shi, Musa Salihu S, Lin Qianying, Ran Jinjun, Yang Guangpu, Wang Weiming, Lou Yijun, Yang Lin, Gao Daozhou, He Daihai, Wang Maggie H
JC School of Public Health and Primary Care, Chinese University of Hong Kong, Hong Kong 999077, China.
Shenzhen Research Institute of Chinese University of Hong Kong, Shenzhen 518060, China.
J Clin Med. 2020 Feb 1;9(2):388. doi: 10.3390/jcm9020388.
In December 2019, an outbreak of respiratory illness caused by a novel coronavirus (2019-nCoV) emerged in Wuhan, China and has swiftly spread to other parts of China and a number of foreign countries. The 2019-nCoV cases might have been under-reported roughly from 1 to 15 January 2020, and thus we estimated the number of unreported cases and the basic reproduction number, , of 2019-nCoV.
We modelled the epidemic curve of 2019-nCoV cases, in mainland China from 1 December 2019 to 24 January 2020 through the exponential growth. The number of unreported cases was determined by the maximum likelihood estimation. We used the serial intervals (SI) of infection caused by two other well-known coronaviruses (CoV), Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS) CoVs, as approximations of the unknown SI for 2019-nCoV to estimate .
We confirmed that the initial growth phase followed an exponential growth pattern. The under-reporting was likely to have resulted in 469 (95% CI: 403-540) unreported cases from 1 to 15 January 2020. The reporting rate after 17 January 2020 was likely to have increased 21-fold (95% CI: 18-25) in comparison to the situation from 1 to 17 January 2020 on average. We estimated the of 2019-nCoV at 2.56 (95% CI: 2.49-2.63).
The under-reporting was likely to have occurred during the first half of January 2020 and should be considered in future investigation.
2019年12月，中国武汉出现了由新型冠状病毒（2019 - nCoV）引起的呼吸道疾病疫情，并迅速蔓延至中国其他地区和一些国家。2020年1月1日至15日期间，2019 - nCoV病例可能存在漏报情况，因此我们估计了漏报病例数以及2019 - nCoV的基本再生数 (R_0)。
我们通过指数增长模型对2019年12月1日至2020年1月24日中国内地2019 - nCoV病例的流行曲线进行了建模。漏报病例数通过最大似然估计法确定。我们使用另外两种知名冠状病毒（CoV），即严重急性呼吸综合征（SARS）冠状病毒和中东呼吸综合征（MERS）冠状病毒引起感染的序列间隔（SI），来近似2019 - nCoV未知的SI，以估计 (R_0)。
我们证实初始增长阶段呈指数增长模式。漏报可能导致2020年1月1日至15日有469例（95%置信区间：403 - 540）漏报病例。与2020年1月1日至17日的情况相比，2020年1月17日之后的报告率平均可能提高了21倍（95%置信区间：18 - 25）。我们估计2019 - nCoV的 (R_0) 为2.56（95%置信区间：2.49 - 2.63）。
漏报很可能发生在2020年1月上半月，未来调查时应予以考虑。
