An investigation of novel coronavirus cases in Chicago details how the virus was spread during family gatherings, including a funeral and birthday party, in an early-release paper published in the U.S. Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.
Researchers found a multifamily cluster of 16 confirmed or probable cases of COVID-19, including three deaths, and traced them back to transmission of SARS-CoV-2 at two family gatherings in February 2020. Fifteen confirmed and probable cases were likely triggered by a chain of transmission that started with one index patient who attended both events. Patients developed symptoms at a median of four days after last contact with a patient with confirmed or probable COVID-19. The three patients who died were all older than 60 years of age and had at least one underlying medical condition.
The researchers conclude that these data support the CDC's social distancing recommendations and stress that U.S. residents should follow stay-at-home orders.