Demographic and clinical characteristics of SARS patients requiring intubation in the Toronto outbreak by presence or absence of transmission to HCWs.

aValues are given as median (lower quartile, upper quartile). bFisher's exact test. cChronic underlying illness is defined as having one or more of diabetes, chronic renal failure, chronic liver disease, chronic obstructive pulmonary syndrome, coronary artery disease, congestive heart failure, active cancer, HIV/AIDS, transplantation. dTransmission occurred from patient to household or hospital contact prior to study period (starting 24 hours prior to intubation).