Medical workers take care of a COVID-19 patient at Union Hospital in Wuhan, China, in April 2020. PHOTO: XINHUA/SHEN BOHAN/GETTY IMAGES On 2 January 2020, a group of clinician-researchers at the Jinyintan Hospital here, along with colleagues at other institutions, launched a study of 41 patients suffering from a new, atypical pneumonia. The team assembled clinical data, laboratory results, and chest x-rays; tracked the production of immune system molecules called cytokines; and noted the use of antivirals, antibiotics, and corticosteroids. Thirteen of the patients required intensive care, and...