A SARS Commentary

Abstract

Health Sciences Centre, Department of Internal Medicine, Winnipeg, Manitoba Correspondence: Dr LE Nicolle, Health Sciences Centre, Department of Internal Medicine, GG443 – 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9. Telephone 204-787-7029, fax 204-787-4826, e-mail nicolle@cc.umanitoba.ca M of Canada viewed the severe acute respiratory syndrome (SARS) epidemic from a distance. Not that those of us outside Toronto were uninvolved – global and national information inundated us; multiple, often simultaneous, teleconferences were repeated daily for information sharing, local contingency plans and national guideline development; and questions from patients, friends and relatives about travel were incessant. This cannot compare, of course, to the magnitude and intensity of the experience of our Toronto colleagues who were actively involved in outbreak management and, in many cases, at personal risk. At this writing, the outbreak is controlled. It may be folly to analyze an experience which remains fluid, but some initial observations seem relevant. The first thought when SARS was reported was that the next pandemic influenza epidemic had arrived. Reports of “bird-flu” in Hong Kong and parts of Europe reinforced this reaction. While initial laboratory testing and the progress of the epidemic rapidly dispelled this possibility, some of the SARS experience is immediately relevant to pandemic influenza assumptions and planning. For instance, it was expected that pandemic influenza would arise in Asia, and that Canada would have several months warning between initial identification of the new virus strain and its North American arrival. SARS certainly arose in Asia, but was not recognized as a global infectious disease emergency until Canada’s largest city, Toronto, was already part of the epidemic. Infrastructure limitations and the lack of transparency in identification and response to the disease in some parts of Asia, together with the realities of international travel, make any expectation of “lead time” less convincing for future planning. Pandemic influenza planning has always assumed that resources for delivery of care would be rapidly overwhelmed. From early in the SARS outbreak, health care workers providing patient care, assisting in the epidemiological investigation or introducing and monitoring control measures experienced considerable stress. Physicians, nurses and public health officials worked long hours for days or weeks with little rest, often in an environment of personal risk or with concern for their colleagues. Fatigued individuals are inefficient, and more likely to make errors. Assistance from the rest of Canada was requested, and some was provided. However, across Canada, assistance that could be made available was limited because local capacities for infectious diseases, infection control and public health were thin. The limited resources elsewhere in Canada were also necessary for local response planning for SARS and maintaining daily health services. Toronto managed the several hundred suspect and probable SARS cases, but the SARS numbers were substantially less than anticipated for an influenza outbreak. A more widespread epidemic, a larger number of patients, or a more prolonged duration of the outbreak may not have been manageable. A surge capacity for public health, clinical care and microbiology for extraordinary national situations such as the SARS outbreak is needed. The development of this capacity will require critical evaluation of the recent experience and strategic planning for the future. The etiologic agent of SARS, a novel coronavirus, was identified promptly through the virtual global laboratory network. However, the story is incomplete – at this writing we do not know the virus origin nor the characteristics that promote human transmission and virulence, nor do we understand infectivity throughout the clinical course. The early triumph in the identification of the etiologic agent was of little practical assistance in managing the epidemic. A rapid and reliable test for accurate diagnosis has not been developed, although intensive investigation is continuing. The clinical case definitions for SARS, appropriately, cast a wide net, and many cases of illness due to other respiratory pathogens were included. The epidemic seems to have been controlled, however, without a reliable diagnostic test or an exact knowledge of transmission characteristics. This SARS epidemic has served notice that the risks of global transmission through air transportation are not theoretical. The potential for rapid dissemination through global travel and trade has been a consistent theme in recent discussions of emerging infections. Despite previous experience, with HIV or West Nile virus, for instance, methods to ameliorate the risks of global spread of illness have not been effectively addressed. With SARS we have seen travel advisories, quarantines, temperature screenings of airline passengers, symptom checks by customs officials and yellow and cherry cards. For much of the world this is a first experience with interventions to prevent potential disease transmission facilitated through global travel.