substantially, for multiple reasons. Elevated anxiety may also have knock-on implications for other health measures (Rubin and Wessely, 2020).By April 10, there were 253 suspected and probable cases in Canada. Two hundred and six of these were in Ontario, the majority in the Toronto area. Ten deaths had occurred, all in Ontario.1 After March 17, most new cases occurred in health care workers.1 Public health efforts to contain the spread of SARS resulted in infection control measures coming to dominate hospital procedures and policy throughout the Toronto area and selected surrounding regions. Provincial public health recommendations, including restricted access to hospitals, screening of employees entering hospitals, isolation precautions and restrictions on transfers of patients between institutions, changed as frequently as daily early in the outbreak. How should a hospital respond to the occupational and psychological challenges that such an outbreak poses to its staff and patients? Despite a large epidemiological literature regarding disease outbreaks, there is little information available to guide interventions to support staff and patients. A report of a 1999 community outbreak of meningococcal disease emphasizes that effective management requires coordination, communication and collaboration.5 A study of a hospital outbreak of vancomycin-resistant enterococci (VRE) describes a severe burden on nursing staff. Nurses assigned to deal with a VRE outbreak were significantly stressed by the sense that they had to function as gatekeepers to the patients for staff and visitors and often felt inadequately supported, blamed for the outbreak and resentful of the increased workload.6 Although several recent disease outbreaks have required an extraordinary public health response, including the Escherichia coli outbreak in Walkerton, Ont.,7 bovine encephalopathy8 and Norwalk virus,9 the SARS outbreak is unique in recent history in its rapidity of transmission, its concentration in health care settings and the large number of health care workers who have been infected. In this paper, we describe the early experience of a university teaching hospital in responding to the psychological and occupational impact of the SARS outbreak upon hospital inpatients with SARS, inpatients without SARS and health care workers. As cases of probable and suspected SARS are identified in other provinces and countries, our experience The immediate psychological and occupational impact of the 2003 SARS outbreak in a teaching hospital ß See related articles pages 1259, 1265, 1289 and 1294 Fast-tracked article, published at www.cmaj.ca on Apr. 16, 2003 Abstract Background: The outbreak of severe acute respiratory syndrome (SARS) in Toronto, which began on Mar. 7, 2003, resulted in extraordinary public health and infection control measures. We aimed to describe the psychological and occupational impact of this event within a large hospital in the first 4 weeks of the outbreak and the subsequent administrative and mental health response. Methods: Two principal authors met with core team members and mental health care providers at Mount Sinai Hospital, Toronto, to compile retrospectively descriptions of the experiences of staff and patients based on informal observation. All authors reviewed and analyzed the descriptions in an iterative process between Apr. 3 and Apr. 13, 2003. Results: In a 4-week period, 19 individuals developed SARS, including 11 health care workers. The hospital’s response included establishing a leadership command team and a SARS isolation unit, implementing mental health support interventions for patients and staff, overcoming problems with logistics and communication, and overcoming resistance to directives. Patients with SARS reported fear, loneliness, boredom and anger, and they worried about the effects of quarantine and contagion on family members and friends. They experienced anxiety about fever and the effects of insomnia. Staff were adversely affected by fear of contagion and of infecting family, friends and colleagues. Caring for health care workers as patients and colleagues was emotionally difficult. Uncertainty and stigmatization