Early Transmission Dynamics in Wuhan, China, of Novel Coronavirus–Infected Pneumonia

Abstract

Background

The initial cases of novel coronavirus (2019-nCoV)–infected pneumonia (NCIP) occurred in Wuhan, Hubei Province, China, in December 2019 and January 2020. We analyzed data on the first 425 confirmed cases in Wuhan to determine the epidemiologic characteristics of NCIP.

Methods

We collected information on demographic characteristics, exposure history, and illness timelines of laboratory-confirmed cases of NCIP that had been reported by January 22, 2020. We described characteristics of the cases and estimated the key epidemiologic time-delay distributions. In the early period of exponential growth, we estimated the epidemic doubling time and the basic reproductive number.

Results

Among the first 425 patients with confirmed NCIP, the median age was 59 years and 56% were male. The majority of cases (55%) with onset before January 1, 2020, were linked to the Huanan Seafood Wholesale Market, as compared with 8.6% of the subsequent cases. The mean incubation period was 5.2 days (95% confidence interval [CI], 4.1 to 7.0), with the 95th percentile of the distribution at 12.5 days. In its early stages, the epidemic doubled in size every 7.4 days. With a mean serial interval of 7.5 days (95% CI, 5.3 to 19), the basic reproductive number was estimated to be 2.2 (95% CI, 1.4 to 3.9).

Conclusions

On the basis of this information, there is evidence that human-to-human transmission has occurred among close contacts since the middle of December 2019. Considerable efforts to reduce transmission will be required to control outbreaks if similar dynamics apply elsewhere. Measures to prevent or reduce transmission should be implemented in populations at risk. (Funded by the Ministry of Science and Technology of China and others.)

Journal

Journal ID (nlm-ta): N Engl J Med

Journal ID (iso-abbrev): N. Engl. J. Med

Journal ID (publisher-id): nejm

Title: The New England Journal of Medicine

Publisher: Massachusetts Medical Society

ISSN (Print): 0028-4793

ISSN (Electronic): 1533-4406

Publication date (Print): 26 March 2020

Volume: 382

Issue: 13

Pages: 1199-1207

Affiliations

From the Chinese Center for Disease Control and Prevention, Beijing (Q.L., X.W., L.Z., R.R., N.X., C.L., D.L., J.Z., W.T., L.J., Q.W., R.W., Y.Z., G. Shi, G.F.G., Z.F.), the Hubei Provincial Center for Disease Control and Prevention, Wuhan, Hubei (X.G., Y.T., X.X., Y.W., Q.C., M.L., C.C., R.Y., S.Z., Y. Luo, B.Y.), the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, University of Hong Kong, Hong Kong (P.W., K.S.M.L., E.H.Y.L., J.Y.W., T.T.Y.L., J.T.W., B.J.C., G.M.L.), the Chinese Field Epidemiology Training Program, Chinese Center for Disease Control and Prevention, Beijing (T.L., R.Y., S.Z., H. Liu, Y. Liu, G. Shao, H. Li, Z.T.), the Jingzhou Center for Disease Control and Prevention, Jingzhou, Hubei (T.L.), the Chengdu Center for Disease Control and Prevention, Chengdu, Sichuan (H. Liu); the Hunan Provincial Center for Disease Control and Prevention, Changsha, Hunan (Y. Liu), the Anyang Municipal Center for Disease Control and Prevention, Anyang, Henan (G. Shao), the Panjin Center for Disease Control and Prevention, Panjin, Liaoning (H. Li), the Guizhou Center for Disease Control and Prevention, Guiyang, Guizhou (Z.T.), the Jiading District Center for Disease Control and Prevention, Shanghai (Y.Y.), the Nanchang Center for Disease Control and Prevention, Nanchang, Jiangxi (Z.D.), the Inner Mongolia Comprehensive Center for Disease Control and Prevention, Hohhot, Inner Mongolia (B.L.), and the Baoshan District Center for Disease Control and Prevention, Shanghai (Z.M.) — all in China.

Author notes

Address reprint requests to Dr. Feng at the Chinese Center for Disease Control and Prevention, No. 155 Changbai Rd., Changping District, Beijing, China, or at fengzj@ 123456chinacdc.cn ; to Dr. G.M. Leung or Dr. Cowling at the School of Public Health, Li Ka Shing Faculty of Medicine, University of Hong Kong, 21 Sassoon Rd., Pokfulam, Hong Kong, China, or at gmleung@ 123456hku.hk or bcowling@ 123456hku.hk , respectively; or to Dr. B. Yang at the Hubei Center for Disease Control and Prevention, No. 35 Zhuodaoquan North Rd., Hongshan District, Wuhan, Hubei, China, or at 49205957@ 123456qq.com .

Drs. Q. Li, X. Guan, P. Wu, and X. Wang and Drs. B. Cowling, B. Yang, M. Leung, and Z. Feng contributed equally to this article.

Article

Publisher ID: NJ202003263821306

DOI: 10.1056/NEJMoa2001316

PMC ID: 7121484

PubMed ID: 31995857

SO-VID: dcf1ebf1-d996-4e52-afc3-62aac50ddcd8

Copyright statement: Copyright © 2020 Massachusetts Medical Society. All rights reserved.

License:

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Funding

Funded by: Ministry of Science and Technology, FundRef http://dx.doi.org/10.13039/501100003711;

Award ID: KJYJ-2013-01-02

Funded by: National Natural Science Foundation of China, FundRef http://dx.doi.org/10.13039/501100001809;

Award ID: 71934002

Funded by: National Institute of Allergy and Infectious Diseases, FundRef http://dx.doi.org/10.13039/100000060;

Award ID: HHSN272201400006C

Funded by: Health and Medical Research Fund, FundRef http://dx.doi.org/10.13039/501100005847;

Categories

Subject: Original Article