III. SARS-CoV Disease: Case Definition and Status as a Nationally Notifiable Disease

Supplement B: SARS Surveillance

Public Health Guidance for Community-Level Preparedness and Response to Severe Acute Respiratory Syndrome (SARS) Version 2/3

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During the 2003 epidemic, CDC and the Council of State and Territorial Epidemiologists (CSTE) developed surveillance criteria to identify persons with SARS. The surveillance case definition changed throughout the epidemic as understanding of the clinical, laboratory, and transmission characteristics of SARS-CoV increased. On June 26, 2003, CSTE adopted a position statement to add SARS-CoV disease [8 pages] to the list of nationally reportable diseases. The position statement included criteria for defining a SARS case for national reporting. On October 30, CSTE issued a new interim position statement [7 pages], with a revised SARS case definition. The position statement and case definition were revised further on November 3. The revised CSTE case definition, subsequently adopted by CDC, will be the basis for ongoing SARS surveillance. Future revisions to the CSTE SARS position statement will be posted on the CSTE website as necessary.

Surveillance case definitions are used primarily for identifying and classifying cases for national reporting purposes. However, for conditions of public health importance such as SARS-CoV disease, disease-control activities should be initiated as soon as possible after a potential case is recognized, even though information sufficient to determine case status may be lacking. Therefore, the revised case definition distinguishes 1) cases of SARS-CoV disease that are classified as confirmed (i.e., clinically compatible illness with laboratory confirmation) or probable (i.e., severe respiratory illness with epidemiologic linkage to a laboratory-confirmed case), from 2) other SARS reports under investigation (RUI), which include patients whose illnesses are less severe or whose exposures to SARS-CoV are not definitive.

Detailed descriptions of revised criteria and classifications for cases of SARS-CoV disease and SARS RUI criteria are provided in Appendix B1 and MMWR of December 12, 2003. SARS case definitions may be modified as the understanding of the clinical, virologic, and transmission characteristics of SARS-CoV evolves. Up-to-date versions of SARS case definitions will be available on CDC's SARS website.