SARS-CoV disease from other febrile respiratory illnesses. Researchers are also working on the development of laboratory tests to improve diagnostic capabilities for SARS-CoV and other respiratory pathogens. To date, however, no specific clinical or laboratory findings can distinguish with certainty SARS-CoV disease from other respiratory illnesses rapidly enough to inform management decisions that must be made soon after the patient presents to the healthcare system. Therefore, early clinical recognition of SARS-CoV disease still relies on a combination of clinical and epidemiologic features.
The diagnosis of SARS-CoV disease and the implementation of control measures should be based on the risk of exposure. In the absence of any person-to-person transmission of SARS-CoV worldwide, the overall likelihood that a patient being evaluated for fever or respiratory illness has SARS-CoV disease will be exceedingly low unless there are both typical clinical findings and some accompanying epidemiologic evidence that raises the suspicion of exposure to SARS-CoV. Therefore, one approach in this setting would be to consider the diagnosis only for patients who require hospitalization for unexplained pneumonia and who have an epidemiologic history that raises the suspicion of exposure, such as recent travel to a previously SARS-affected area (or close contact with an ill person with such a travel history), employment as a healthcare worker with direct patient contact or as a worker in a laboratory that contains live SARS-CoV, or an epidemiologic link to a cluster of cases of unexplained pneumonia. Once person-to-person SARS-CoV transmission has been documented anywhere in the world, the positive predictive value of even early clinical symptoms (e.g., fever or lower respiratory symptoms in the absence of pneumonia), while still low, may be sufficiently high—when combined with an epidemiologic link to settings in which SARS-CoV has been documented—to lead clinicians to consider a diagnosis of SARS-CoV disease.
In that context, the guidance that follows should be considered in the evaluation and management of patients who present from the community with fever or lower respiratory illnesses. For more detailed guidance on infection control, see Supplement I in Public Health Guidance for Community-Level Preparedness and Response to Severe Acute Respiratory Syndrome (SARS): http://www.cdc.gov/ncidod/sars/guidance/index.htm.