Contact Tracing ID'd Large Multifamily COVID-19 Cluster in Chicago
Findings highlight the importance of adhering to current social distancing recommendations
FRIDAY, April 10, 2020 (HealthDay News) -- One index patient with COVID-19 and only mild symptoms attended two family gatherings and likely triggered a chain of transmission that included 15 other confirmed and probable cases with three deaths, according to research published in the April 8 early-release issue of the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.
Isaac Ghinai, M.B.B.S., from the Chicago Department of Public Health, and colleagues investigated a large multifamily cluster of 16 COVID-19 cases (seven confirmed and nine probable). Interviews were conducted with patients with confirmed COVID-19 and their close contacts (age range from 5 to 86 years) to better understand nonhousehold, community transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from a cluster likely resulting from transmission of SARS-CoV-2 at two family gatherings (a funeral and a birthday party).
The researchers found that the median interval from last contact with a patient with confirmed or probable COVID-19 to first symptom onset was four days. Fifteen people were likely infected, including three who died, within three weeks after mild respiratory symptoms were noted in the index patient. With no household contacts and only mild symptoms for which medical care was not sought, the index patient was able to transmit infection to 10 other people. Use of common serving dishes, physical embraces, and providing limited personal care, while wearing no personal protective equipment, may have been sources of transmission.
"Extended family gatherings (a birthday party, funeral, and church attendance), all of which occurred before major social distancing policies were implemented, might have facilitated transmission of SARS-CoV-2 beyond household contacts into the broader community," the authors write.