Toronto SARS Outbreak

 

Toronto is the capital of Ontario, Canada. It is Canada's largest city and home to more than 2.5 million people of diverse backgrounds and origins. Toronto is also the site of North America's largest outbreak of SARS. Between February and July 2003, in response to the SARS crisis, Toronto fielded more than 316,000 hotline calls, quarantined 23,000 people, investigated more than 2,000 potential cases, confirmed 358 of them as SARS, and suffered 38 deaths.1

The human and financial impact of this outbreak on the city was enormous. Of the 358 people confirmed to have SARS in the Toronto area, 225 were Toronto residents. Of these, 24 percent required placement in an intensive care unit, 83 percent survived, and 17 percent died. The financial impact, fueled by the disease itself and a travel advisory from the World Health Organization, was significant. The province of Ontario estimated total losses at 1.13 billion in Canadian dollars, with the tourist industry suffering a decline of 260 million in Canadian dollars. And 11 percent of Toronto's tourism-related businesses initiated layoffs.2,3

How did this happen? It began with a single index case -- a Toronto resident returning home ill from a visit to Hong Kong. On March 5, 2003, she died at home. On March 7, her son was admitted to the hospital, critically ill. Six days later, he died. The following day, March 14, four other family members were admitted with the illness. Within one week, the first cases in hospital staff began to appear, and four days later, the hospital was closed. The closure necessitated the transfer of patients to other Toronto hospitals. There are a total of 19 acute-care hospitals serving the city, and, ultimately, 11 of them were drawn into the epidemic. This occurred as the infection spread rapidly through the hospitals, primarily through mucus secretions and respiratory droplets. Before it was over, staff, patients, family, and friends would be affected, and the city paralyzed.1

Seventy percent of the people infected with SARS were exposed to it in hospitals. Outside hospitals, the most common sites of exposure included work and school, which accounted for nearly 20 percent of the cases. 1

As bad as the situation was, it could have been a great deal worse had it not been for Toronto's strong public health response. All hospitals with SARS cases were evaluated by expert public health teams, which worked in unison with medical and nursing staffs. All non-essential hospital employees were immediately barred from the facilities. All elective surgery cases and outpatient visits were cancelled. All staff, patients, and visitors were screened for SARS. Universal precautions were implemented and N95 super screener respirators were used for protection by caregivers. All contacts of those infected were vigorously pursued, identified and evaluated. All close contacts were quarantined at home for 10 days, with careful instruction and monitoring to avoid family cross infection. And, in two cases, when there was a resurgence of the infection, the causes were quickly identified and addressed.1

What lessons should we take away from this event? Clearly, it doesn't take much in the modern world to create an epidemic. One individual, intentionally or unintentionally, can get the ball rolling for a population that is unaware. SARS spread because it was initially unrecognized, not because it was untreatable or impossible to contain.

Once recognized, infection-control strategies worked. These included aggressive pursuit of contacts, shutting down the sources, quarantining potential future cases, and effectively interfacing public health specialty teams with clinical hospital leadership. For the future, we now know that team readiness, a high index of suspicion, close monitoring, good planning, and vigilance are key to controlling outbreaks like the one Toronto endured.1

For Health Politics, I'm Mike Magee.

References

1.Svoboda T, Henry B, Shulman L, et al. Public health measures to control the spread of the severe acute respiratory syndrome during the outbreak in Toronto. NEJM. 2004;350:2352-2361.

2.The impact of SARS on Toronto's business community: a survey of Toronto employers. Toronto: Toronto Board of Trade; May 2003. Cited in Svoboda T, Henry B, Shulman L, et al.

3.Toronto tourism revenue loss exceeds quarter of a billion [press release]. Toronto: KPMG Canada; July 2, 2003. Cited in Svoboda T, Henry B, Shulman L, et al.