This
is Appendix 1 of Supplement B of the Public
Health Guidance for Community-Level Preparedness ansonse to Severe
Acute Respiratory Syndrome (SARS).
December 2003
Clinical
Criteria
Early
illness
- Presence
of two or more of the following features: fever (might be subjective),
chills, rigors, myalgia, headache, diarrhea, sore throat, rhinorrhea
Mild-to-moderate
respiratory illness
- Temperature
of >100.4º F (>38º C) 1 and
- One or
more clinical findings of lower respiratory illness (e.g., cough,
shortness of breath, difficulty breathing)
Severe
respiratory illness
- Meets
clinical criteria of mild-to-moderate respiratory illness, and
- One or
more of the following findings:
- Radiographic
evidence of pneumonia, or
- Acute
respiratory distress syndrome, or
- Autopsy
findings consistent with pneumonia or acute respiratory distress
syndrome without an identifiable cause
Epidemiologic
Criteria
Possible
exposure to SARS-associated coronavirus (SARS-CoV)
One or
more of the following exposures in the 10 days before onset of symptoms:
- Travel
to a foreign or domestic location with documented or suspected recent
transmission of SARS-CoV 2 or
- Close
contact 3 with a person with mild-to-moderate or severe respiratory
illness and with history of travel in the 10 days before onset of
symptoms to a foreign or domestic location with documented or suspected
recent transmission of SARS-CoV 2
Likely
exposure to SARS-CoV
One or more
of the following exposures in the 10 days before onset of symptoms:
- Close
contact3 with a confirmed case of SARS-CoV disease or
- Close
contact3 with a person with mild-moderate or severe respiratory
illness for whom a chain of transmission can be linked to a confirmed
case of SARS-CoV disease in the 10 days before onset of symptoms
Laboratory
Criteria
Tests to
detect SARS-CoV are being refined, and their performance characteristics
assessed; therefore, criteria for laboratory diagnosis of SARS-CoV
are changing4. The following are the general criteria for
laboratory confirmation of SARS-CoV:
- Detection
of serum antibody to SARS-CoV by a test validated by CDC (e.g., enzyme
immunoassay [EIA]), or
- Isolation
in cell culture of SARS-CoV from a clinical specimen, or
- Detection
of SARS-CoV RNA by a reverse-transcription-polymerase chain reaction
(RT-PCR) test validated by CDC and with subsequent confirmation in
a reference laboratory (e.g., CDC)
Information
regarding the current criteria for laboratory diagnosis of SARS-CoV
is available at www.cdc.gov/ncidod/sars/labdiagnosis.htm.
Exclusion
Criteria
A person
may be excluded as a SARS report under investigation (SARS RUI), including
as a CDC-defined probable SARS-CoV case, if any of the following applies:
- An alternative
diagnosis can explain the illness fully5
- Antibody
to SARS-CoV is undetectable in a serum specimen obtained > 28
days after onset of illness6
- The case
was reported on the basis of contact with a person who was excluded
subsequently as a case of SARS-CoV disease; then the reported case
also is excluded, provided other epidemiologic or laboratory criteria
are not present
Case Classification
SARS RUI
Reports
in persons from areas where SARS is not known to be active:
- SARS
RUI-1 : Patients with severe illness compatible with SARS in groups
likely to be first affected by SARS-CoV7 if SARS-CoV is introduced
from a person without clear epidemiologic links to known cases of
SARS-CoV disease or places with known ongoing transmission of SARS-CoV
Reports
in persons from areas where SARS activity is occurring:
- SARS
RUI-2 : Patients who meet the current clinical criteria for mild-to-moderate
illness and the epidemiologic criteria for possible exposure (spring
2003 CDC definition for suspect cases8)
- SARS
RUI-3 : Patients who meet the current clinical criteria for severe
illness and the epidemiologic criteria for possible exposure (spring
2003 CDC definition for probable cases8)
- SARS
RUI-4 : Patients who meet the clinical criteria for early or mild-moderate
illness and the epidemiologic criteria for likely exposure to SARS-CoV
SARS-CoV
disease classification
- Probable
case of SARS-CoV disease: in a person who meets the clinical criteria
for severe respiratory illness and the epidemiologic criteria for
likely exposure to SARS-CoV
- Confirmed
case of SARS-CoV disease: in a person who has a clinically compatible
illness (i.e., early, mild-to-moderate, or severe) that is laboratory
confirmed
_________
1 A
measured documented temperature of >100.4º F (>38º C)
is expected. However, clinical judgment may allow a small proportion
of patients without a documented fever to meet this criterion. Factors
that might be considered include patient's self-report of fever,
use of antipyretics, presence of immunocompromising conditions or
therapies, lack of access to health care, or inability to obtain
a measured temperature. Initial case classification based on reported
information might change, and reclassification might be required.
2 Types
of locations specified will vary (e.g., country, airport, city, building,
floor of building). The last date a location may be a criterion for
exposure for illness onset is 10 days (one incubation period) after
removal of that location from CDC travel alert status. The patient's
travel should have occurred on or before the last date the travel alert
was in place. Transit through a foreign airport meets the epidemiologic
criteria for possible exposure in a location for which a CDC travel
advisory is in effect. Information regarding CDC travel alerts and
advisories and assistance in determining appropriate dates are available
at www.cdc.gov/ncidod/sars/travel.htm.
3 Close
contact is defined as having cared for or lived with a person with
SARS or having a high likelihood of direct contact with respiratory
secretions and/or body fluids of a person with SARS (during encounters
with the patient or through contact with materials contaminated by
the patient) either during the period the person was clinically ill
or within 10 days of resolution of symptoms. Examples of close contact
include kissing or embracing, sharing eating or drinking utensils,
close conversation (<3 feet), physical examination, and any other
direct physical contact between persons. Close contact does not include
activities such as walking by a person or sitting across a waiting
room or office for a brief time.
4 The
identification of the etiologic agent of SARS (SARS-CoV) led to the
rapid development of EIAs and immunofluorescence assays (IFAs) for
serologic diagnosis and RT-PCR assays for detection of SARS-CoV RNA
in clinical samples. These assays can be very sensitive and specific
for detecting antibody and RNA, respectively, in the later stages of
SARS-CoV disease. However, both are less sensitive for detecting infection
early in illness. The majority of patients in the early stages of SARS-CoV
disease have a low titer of virus in respiratory and other secretions
and require time to mount an antibody response. SARS-CoV antibody tests
might be positive as early as 8-10 days after onset of illness and
often by 14 days after onset of illness, but sometimes not until 28
days after onset of illness. Information regarding the current criteria
for laboratory diagnosis of SARS-CoV is available at www.cdc.gov/ncidod/sars/labdiagnosis.htm.
5 Factors
that may be considered in assigning alternate diagnoses include the
strength of the epidemiologic exposure criteria for SARS-CoV disease,
the specificity of the alternate diagnostic test, and the compatibility
of the clinical presentation and course of illness for the alternative
diagnosis.
6 Current
data indicate that >95% of patients with SARS-CoV disease mount
an antibody response to SARS-CoV. However, health officials may choose
not to exclude a case based on lack of a serologic response if reasonable
concern exists that an antibody response could not be mounted.
7 Consensus
guidance between CDC and CSTE on which groups are most likely to be
first affected by SARS-CoV if it re-emerges is in development. In principle,
SARS-CoV disease should be considered at a minimum in the differential
diagnosis for persons requiring hospitalization for radiographically
confirmed pneumonia or acute respiratory distress syndrome without
identifiable etiology and who have one of the following risk factors
in the 10 days before the onset of illness:
- Travel
to mainland China, Hong Kong, or Taiwan, or close contact with
an ill person with a history of recent travel to one of these areas, or
- Employment
in an occupation associated with a risk for SARS-CoV exposure (e.g.,
healthcare worker with direct patient contact or worker in a laboratory
that contains live SARS-CoV), or
- Part
of a cluster of cases of atypical pneumonia without an alternative
diagnosis
Guidelines
for the identification, evaluation, and management of these persons
are available at www.cdc.gov/ncidod/sars/absenceofsars.htm.
8 During
the 2003 SARS epidemic, CDC case definitions were the following:
Suspect
case
- Meets
the clinical criteria for mild-to-moderate respiratory illness and
the epidemiologic criteria for possible exposure to SARS-CoV but
does not meet any of the laboratory criteria and exclusion criteria or
- Unexplained
acute respiratory illness resulting in death in a person on whom
an autopsy was not performed and who meets the epidemiologic criteria
for possible exposure to SARS-CoV but does not meet any of the laboratory
criteria and exclusion criteria
Probable
case
- Meets
the clinical criteria for severe respiratory illness and the epidemiologic
criteria for possible exposure to SARS-CoV but does not meet any
of the laboratory criteria and exclusion criteria
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