On January 23, 2020, Illinois reported the state's first laboratory-confirmed case (index case) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19, in a woman in her 60s who had returned from Wuhan, China in mid-January. Subsequently, the first evidence of secondary transmission in the USA was reported on January 30, when her husband, who had not traveled outside the USA but who does suffer from chronic obstructive pulmonary disease (COPD) and chronic cough, had frequent, close contact with his wife since her return and while she was symptomatic, tested positive for SARS-CoV-2.