Surveillance
of contacts of SARS cases is essential to control efforts. Rapid identification,
evaluation, and monitoring of exposed asymptomatic contacts and prompt
isolation of those who are found to be clinically ill can prevent further
transmission of disease.
Infectiousness
in patients with SARS-CoV disease appears to begin with the onset of
clinical illness. Although the exact duration of infectiousness is
not known, it is recommended that patients with SARS-CoV disease avoid
contact with other persons for up to 10 days after resolution of fever
and improving or absent respiratory symptoms. Contact tracing is the
systematic identification of persons who may have been exposed to patients
with suspected or confirmed SARS-CoV disease during the infectious
period. In some instances, public health officials should also consider
identifying persons who had contact with a SARS patient before the
patient's onset of illness - if there is a chance that the contacts
might have been exposed to the same source of infection as the case.
Such situations would include those in which the SARS patient's source
of infection is unclear or not previously recognized (e.g., an index
case among a group of tourists).
Objective
1: Prepare to conduct surveillance of contacts by ensuring
the availability of personnel and other resources.
Activities:
State and local health departments
- Designate
one person to coordinate activities related to contact tracing, interviewing,
evaluation, and monitoring.
- Identify
additional personnel to manage contact tracing and monitoring in
different regions of the state. Personnel can be provided from state
or other resources as needed. Ideally, select staff with field experience
involving contact tracing (e.g., from STD, TB, or HIV control programs).
- As needed,
modify and adopt sample forms provided by CDC (Appendix
B3).
Additional
recommendations related to preparedness planning for surveillance and
management of SARS contacts, including community containment measures
such as non-hospital isolation and quarantine, are provided in Supplement
D.
Objective
2: Identify all contacts of all SARS cases.
Activities:
State and local health departments
- Identify
contacts of known or possible cases of SARS-CoV disease. Obtain information
from the case-patient, next of kin, workplace representative, or
others with appropriate knowledge of the case-patient's recent whereabouts
and activities.
- Trace
each contact whose name, address, and/or telephone number is provided.
- When
contact information is unknown or incomplete, use a variety of resources
(e.g., work and school contact numbers, telephone directories, voting
lists, neighborhood interviews, site visits, visits to " " hangouts")
to trace contacts. If contacts cannot be found through these mechanisms,
other methods for notifying potential contacts (e.g., media announcements)
may have to be considered.
- Locate
and interview each contact to: 1) confirm exposure to the SARS case,
2) document the presence or absence of fever or lower respiratory
symptoms3,
and 3) identify additional contacts.
- For persons
who are free of symptoms at the time of interview, initiate plans
for ongoing symptom monitoring or other restrictions implemented
by public health officials (see Supplement
D) for 10 days after the last contact with the SARS case.
Objective
3: Prioritize contacts on the basis of estimated risk of
exposure if necessary.
Contact
tracing should include detailed interviews so that contacts can be
prioritized on the basis of their estimated risk of SARS-CoV exposure.
This process allows identification of the contacts at greatest risk
and more efficient use of the resources needed for follow-up and monitoring.
In some instances, however, resource limitations (e.g., limited number
of skilled interviewers) or large numbers of potential contacts may
preclude focused contact tracing and require follow-up and monitoring
of a large number of contacts with less definite risks.
Activities:
State and local health departments
- Consider
establishing priorities among contacts based on the following factors:
- Probability
of SARS-CoV disease in the index case (e.g., contacts of confirmed
and probable SARS-CoV cases would be highest priority)
- Duration
and spatial proximity (e.g., < 3 feet) of the contact's exposure
to the case
- History
of exposure(s) known or suspected to be at higher risk for transmission
(e.g., SARS patient care; participation in an aerosol-generating
procedure; intimate contact)
- Documented
secondary cases resulting from exposure to the index patient
- After
a review of contact priority lists and available resources, state
authorities may decide to adopt different levels of contact follow-up
and monitoring activities for different categories of contacts. For
detailed recommendations for management of contacts, see Supplement
D.
3 For
persons with a high risk of exposure to SARS-CoV (e.g., persons previously
identified through contact tracing or self-identified as close contacts
of a laboratory-confirmed case of SARS-CoV disease; persons who are
epidemiologically linked to a laboratory-confirmed case of SARS-CoV
disease), clinical criteria should be expanded to include, in addition
to either fever or lower respiratory symptoms, the presence of any
of the early symptoms of SARS-CoV disease (i.e., chills, rigors, myalgia,
headache, diarrhea, sore throat, rhinorrhea) as a potential trigger
to initiate a clinical evaluation for SARS-CoV disease.
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