Transmission of severe acute respiratory syndrome coronavirus 2 to close contacts, China, january-february 2020

Abstract

We estimated the symptomatic, PCR-confi rmed secondary attack rate (SAR) for 2, 382 close contacts of 476 symptomatic persons with coronavirus disease in Yichang, Hubei Province, China, identifi ed 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 <18 years of age to 12.5% for those >60 years of age. Multilevel logistic regression showed that factors signifi cantly associated with increased SAR were living together, being a spouse, and being >60 years of age. Multilevel regression did not support SAR diff ering signifi cantly 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.