Emerging Infectious Diseases (Sep 2021)

Transmission of Severe Acute Respiratory Syndrome Coronavirus 2 to Close Contacts, China, January–February 2020

  • Yu Li,
  • Jianhua Liu,
  • Zhongcheng Yang,
  • Jianxing Yu,
  • Chengzhong Xu,
  • Aiqin Zhu,
  • Hao Zhang,
  • Xiaokun Yang,
  • Xin Zhao,
  • Minrui Ren,
  • Zhili Li,
  • Jinzhao Cui,
  • Hongting Zhao,
  • Xiang Ren,
  • Chengxi Sun,
  • Ying Cheng,
  • Qiulan Chen,
  • Zhaorui Chang,
  • Junling Sun,
  • Lance E. Rodewald,
  • Liping Wang,
  • Luzhao Feng,
  • George F. Gao,
  • Zijian Feng,
  • Zhongjie Li

DOI
https://doi.org/10.3201/eid2709.202035
Journal volume & issue
Vol. 27, no. 9
pp. 2288 – 2293

Abstract

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We estimated the symptomatic, PCR-confirmed secondary attack rate (SAR) for 2,382 close contacts of 476 symptomatic persons with coronavirus disease in Yichang, Hubei Province, China, identified during January 23–February 25, 2020. The SAR among all close contacts was 6.5%; among close contacts who lived with an index case-patient, the SAR was 10.8%; among close-contact spouses of index case-patients, the SAR was 15.9%. The SAR varied by close contact age, from 3.0% for those 60 years of age. Multilevel logistic regression showed that factors significantly associated with increased SAR were living together, being a spouse, and being >60 years of age. Multilevel regression did not support SAR differing significantly by whether the most recent contact occurred before or after the index case-patient’s onset of illness (p = 0.66). The relatively high SAR for coronavirus disease suggests relatively high virus transmissibility.