By Richard Aghababian, MD
Vol. 12, Issue 3, July 2003
It is unusual to pick up a newspaper or magazine these days without seeing a headline about the worldwide epidemic of Severe Acute Respiratory Syndrome (SARS). In a matter of weeks, this epidemic disease has severely undermined the tourism industry and injured the economies of several Asian counties and one major Canadian city. It has been estimated that the city of Hong Kong alone has lost $5 billion as of mid-May. SARS first caught the attention of the global media in early March when cases began appearing in Hong Kong. One of the first cases described was a doctor from Guangzhou, China who spread the disease to six people on his floor of the Metropole in Hong Kong. Medical workers who cared for the doctor and the six hotel guests began contracting the infection. On March 12, 2003, the World Health Organization issued a worldwide alert concerning this infectious disease. Further investigation soon revealed that a similar illness had begun to appear in the Chinese province of Guandgong in November 2002. On March 22, 2003, the Centers for Disease Control and Prevention (CDC) provided an initial interim case description for SARS. The internal US surveillance case definition was updated on April 30, 2003. (Attachment A)
The global impact of this infectious disease outbreak was amplified to some degree by pre-existing fears that a terrorist group or cell might unleash a particularly virulent and possibly heretofore unknown microbiologic agent to draw attention to the conflict in the Middle East or to the nuclear weapons standoff in North Korea. Careful study of the appearance of new cases over time, and admissions by Chinese authorities that they first became aware of the disease in November of 2002, made it seem most likely that SARS was the result of a naturally occurring viral mutation rather than a bioterrorism plot. Recent information suggests that the mutation or mutations that produced the implicated SARS strain of the corona virus may have first appeared in animals before infecting humans.
Investigation of the epidemic has suggested that viable organisms are most likely contained in aero sized droplets produced from the secretions of infected individuals. Once expelled, the virus appears to remain viable in air or on inanimate objects (such as a doorknob or countertop) for a short period of time. Healthcare workers (HCWs) are particularly vulnerable. When a patient sneezes, coughs, or vomits in the presence of an HCW, the disease may be readily transmitted. Eye protection, N95 fit tested respirators, gowns, and gloves should be employed by HCWs when caring for suspected SARS patients. Patients with suspected SARS should be cared for in a negative pressure isolation room to minimize the potential for spread of the disease until the diagnosis can be ruled out. Milder cases of SARS should be managed at home or in specifically designated facilities to prevent avoidable temporary closure of acute care hospitals. Mortality rates for SARS patients have varied considerably between different countries. Reported mortality rates have varied from 3% to 15%. Mortality rates are higher for older patients.
Laboratory confirmation of the diagnosis of SARS occurs when SARS associated corona virus (SARS-CoV) is detected in the serum. Evidence of virus in clinical specimens is demonstrated by reverse transcriptase polymerase chain reaction analysis or by detection of antibody to SARS-CoV in convalescent serum obtained more than 21 days after symptom onset. Currently, most hospitals must send their specimens to a central laboratory (in Massachusetts specimens are being sent to the CDC in Atlanta as of 5/12/03). Therefore, patients suspected to have SARS must be treated while acutely ill without diagnostic confirmation. While clinicians should handle suspected SARS patients with great caution to avoid spread of the disease, diagnostic work-ups of patients with acute respiratory failure should be thorough since other disease processes, including infections by other organisms, can produce similar clinical presentations. Acute heart failure and pulmonary emboli are examples of other etiologies that can initially mimic SARS.
Several treatment regimens have been proposed for patients with SARS including the use of antiviral agents and corticosteriods. Thus far, none of the proposed regimens have been proven to be clearly beneficial treatment, therefore supportative therapy and antibiotics are suggested to treat secondary infections.
Regardless of the precautions taken by HCWs, the risk of acquiring the disease while caring for acutely ill patients in the emergency department, intensive care unit, isolation ward, or operating room cannot be totally eliminated. Since the airway of the SARS patient is the major source of infecting organisms, HCWs involved in airway management or hygiene are particularly vulnerable. HCWs are trained to instinctively respond to the immediate needs of a patient. Providing mouth-to-mouth ventilation to a patient who suddenly goes into cardiopulmonary arrest for example. Reconsideration of how acute airway and breathing situations should be managed when the etiology of the patient’s acute distress is unknown may be appropriate at this time. Perhaps certain HCWs should either carry or have immediate access to kits containing barrier devices and protective clothing at all times. Perhaps janitors need to wear protective equipment when cleaning up after SARS patients, since a janitor in a Taiwan Hospital was responsible for the spread of the disease to several others at his hospital.
What should be done when a HCW is exposed to a patient with SARS? The incubation period is currently thought to be typically 10 to 14 days. Is quarantine or furlough of exposed HCWs appropriate and fair? What are the psychological and financial consequences of exposure or acquisition of the disease? How will fellow HCWs’ family members and friends react to an exposed or infected HCW? These issues should be openly discussed by medical leadership, preferably before the first care of SARS appears at any given acute care facility.
It is unfortunate that the SARS epidemic surfaced in 2003, a year filled with many other global frights. Few of us have had experience with such a rapid and widespread outbreak of a contagious infectious disease. However, it should be remembered that the 1918 influenza epidemic which killed over 20 million people was much worse than the current SARS outbreak and was rivaled only by the European Plague epidemic of 1346. The outbreak of Legionnaire’s disease that was first noted in a Philadelphia hotel in 1976 is not dissimilar to the SARS epidemic. While the current SARS epidemic appears to have been an act of nature, the global response to this scourge should be viewed as an opportunity to prepare us for response to ponder our state of readiness to a bio terrorist attack. The response to an intentional release of a virus such as smallpox or ebola must be more efficient if we are to minimize the loss of life as best we can. Fortunately, many microbial agents that may be used by terrorists can be contained by implementing efficient isolation protocols and focused vaccination programs. While we cannot eliminate naturally occurring or intentionally perpetrated epidemics, knowledge and rapid response can decrease their impact.
Summary of the lessons learned from the current SARS epidemic:
- HCWs are at the "front line" when it comes to the management of nationally occurring or intentionally perpetrated infectious epidemics.
- SARS should be in the initial differential diagnosis when a patient appears with acute respiratory distress. Always ask about travel or exposure to others with the disease and immediately take proper precautions.
- Infectious epidemics should be considered whenever clusters of patients with similar acute symptoms begin to appear for care.
- Every physician, nurse, and emergency medical technician (EMT) should attend a course designed to review the basic principles of epidemiology.
- Individuals who become ill with an infectious disease should not be penalized, but discouraged from traveling until they have returned to good health.
- SARS should remind us how vulnerable we are to the rapid spread of infectious disease, particularly given the ease of travel in the modern era.
- Additional information concerning SARS can be obtained from the CDC’s Web site.
