*amOR, adjusted matched odds ratio; COVID-19, coronavirus disease; IQR, interquartile range; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2. †Model included 967 healthcare personnel: 345 cases and 622 controls. Among these, there were 71 pairs of 1 case and 1 control, 271 clusters of 1 case and 2 controls, and 3 clusters of 1 case and 3 controls. ‡In the 14 d before illness onset or SARS-CoV-2 virus test specimen collection date. §15 cases and 14 controls reported that they did not know if they had close contact with persons with COVID-19 outside the workplace; data were missing for 1 control. ¶15 cases and 27 controls reported that they did not know if they had close contact with COVID-19 patients in the workplace; data were missing for 1 control. #Age was not reported for 6 controls; these healthcare personnel were grouped as <30 y. **Asthma, rhinitis, chronic obstructive pulmonary disease or other chronic lung diseases, hypertension or heart conditions, diabetes mellitus, chronic kidney disease or hemodialysis, autoimmune or rheumatologic disease, active cancer, solid organ or hematopoietic stem cell transplant, other immunosuppressing conditions, chronic liver disease, pregnancy, current or recent smoking (i.e., within a year of SARS-CoV-2 virus test specimen collection date), and obesity or severe obesity with body mass index >30. ††Race was not reported for 16 cases and 27 controls; ethnicity was missing for 14 cases and 24 controls. ‡‡Dental healthcare provider, emergency medical services personnel, licensed practical nurse, nurse practitioner, occupational therapist, other nurse, physician assistant, physical therapist or assistant, phlebotomist, respiratory therapist, radiology technician, speech-language pathologist, and surgical, medical, or emergency technician. §§Nonphysician behavioral health provider, chaplain, care coordinator, dietician, environmental services personnel, food services personnel, patient transport personnel, research personnel, social worker, or student. ¶¶Facilities maintenance personnel, medical equipment technician, laboratory personnel, or pharmacist. Detailed healthcare roles and area of the facility in which HCP worked are available in Appendix Tables 2 and 3 (https://wwwnc.cdc.gov/EID/article/28/1/21-1803-App1.pdf).