Investigation of Contacts of Persons with Infectious

Tuberculosis, 2005

Division of Tuberculosis EliminationCenters for Disease Control and Prevention

National Tuberculosis Controllers AssociationCenters for Disease Control and Prevention

Investigation of Contacts of Persons with Infectious

Tuberculosis, 2005 CHALLENGE: How to fit 50 pages ofNEW recommendationsinto 15 minutes??

5

Contents – “Soup to nuts” 

Purpose Summary 1. Introduction and Background 7. Expanding Contact

Investigations

2. Decision to Initiate a Contact Investigation 8. Data Management and

Evaluation

3. Investigation of the Presenting Patient 9. Confidentiality and Consent

4. Prioritization of Contacts 10. Staffing and Training for Contact Investigations

5. Evaluation of Contacts 11. Contact Investigations in Special Circumstances

6. Medical Management of Contacts 12. Source Case Investigations

  13. Special Topics 

 

Decisions to Initiate a Contact Investigation

Decision to Initiate a TB Contact Investigation

*Acid-fast bacilli†Nucleic acid assay§Approved indication for NAA¶Chest radiograph

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Investigating the Index Patient and Sites of Transmission

PHASES• Pre-interview• Determining the infectious period• Interviewing the patient• Proxy interview• Field investigation• Follow up steps• Specific investigation plan

Estimating the Beginning of the Infectious PeriodCharacteristic of Index Case

TB symptoms AFB sputum smear positive

Cavitary chest radiograph

Likely period of infectiousness

Yes No No 3 months before symptom onset or 1st positive finding consistent with TB disease, whichever is longer

Yes Yes Yes 3 months before symptom onset or 1st positive finding consistent with TB disease, whichever is longer

No No No 4 weeks before date of suspected diagnosis

No Yes Yes 3 months before positive finding consistent with TB

SOURCE: California Department of Health Services Tuberculosis Control Branch; California Tuberculosis Controllers Association. Contact Investigation Guidelines. Berkley, CA: California Department of Health Services; 1998.

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PHASES• Pre-interview• Determining the infectious period• Interviewing the patient• Proxy interview• Field investigation - potential sites of

transmission• Follow up steps - frequent reassessments• Specific investigation plan

Exposure Period for Contacts

Determined by: how much time the contact spent with the index patient during the infectious period

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Goal = PREVENTION

Assigning Priorities to Contacts

• Priorities should be assigned to contacts and resources allocated to complete all investigative steps for high-and medium-priority contacts.

• Any contact not classified as high or medium priority is assigned a low priority.

Factors for Assigning Contact Priorities

• Characteristics of the index patient• Characteristics of contacts• Age• Immune status• Other medical conditions• Exposure

Prioritization of Contacts (1)Patient has pulmonary, laryngeal, or pleural TB with cavitary lesion on chest radiograph or is AFB sputum smear positiveHousehold contact HighContact <5 years of age HighContact with medical risk factor (HIV or other medical risk factor)

High

Contact with exposure during medical procedure (bronchoscopy, sputum induction, or autopsy)

High

Contact in a congregate setting HighContact exceeds duration/environment limits (limits per unit time established by the health department for high-priority contacts)

High

Contact is ≥ 5 years and ≤ 15 years of age MediumContact exceeds duration/environment limits (limits per unit time established by the health department for medium-priority contacts)

Medium

Any contact not classified as high or medium priority is assigned a low priority.

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Prioritization of Contacts (2)Patient is a suspect or has confirmed pulmonary/pleural TB – AFB smear negative, abnormal chest radiograph consistent with TB disease, may be NAA and/or culture positiveContact <5 years of age HighContact with medical risk factor (e.g., HIV) HighContact with exposure during medical procedure (bronchoscopy, sputum induction, or autopsy)

High

Household contact MediumContact exposed in congregate setting MediumContact exceeds duration/environment limits (limits per unit time established by the local TB control program)

Medium

Any contact not classified as high or medium priority is assigned a low priority.

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Diagnostic and Public Health Evaluation of Contacts

Initial Assessment of Contacts

• Should be accomplished within 3 working days of the contact having been listed in the investigation

• Gathers background health information

• Permits face-to-face assessment of person’s health

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Tuberculin Skin Testing• All high or medium priority contacts who do

not have a documented previous positive tuberculin skin test (TST) or previous TB disease should receive a TST at the initial encounter.

• If not possible, TST should be administered– ≤7 working days of listing high-priority contacts– ≤14 days of listing medium-priority contacts

Postexposure Tuberculin Skin Testing

• Window period is 8–10 weeks after exposure ends

• Contacts who have a positive result after a previous negative result are said to have had a change in tuberculin status from negative to positive

Medical EvaluationAll contacts whose skin test reaction induration is ≥5 mm or who report any symptoms consistent with TB disease should undergo further examination and testing for TB

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Evaluation and Follow-up of Children <5 Years of Age

• Always assigned a high priority as contacts• Should receive full diagnostic medical evaluation,

including a chest radiograph• If TST ≤5 mm of induration and last exposure <8 weeks,

LTBI treatment recommended (after TB disease excluded)• Second TST 8–10 weeks after exposure; decision to treat

is reconsidered– Negative TST – treatment discontinued– Positive TST – treatment continued See Figure 7 (algorithm)

Evaluation and Follow-up of Immunosuppressed Contacts

• Should receive full diagnostic medical evaluation, including a chest radiograph

• If TST negative ≥8 weeks after end of exposure, full course of treatment for LTBI recommended (after TB disease is excluded)

See Figure 6 (algorithm)

Medical Treatment for Contacts with LTBI

Window-Period Prophylaxis

• The frequency, duration, and intensity of exposure

• Corroborative evidence of transmission from the index patient

Decision to treat contacts with a negative skin test result should take the following factors into consideration

Health Department Responsibilities

• Focusing resources on contacts in most need of treatment

• Monitoring treatment, including that of contacts who receive care outside the health department

• Providing directly observed therapy (DOT), incentives, and enablers

Selecting Contacts for Directly Observed Therapy

• Contacts aged <5 years• Contacts who are HIV infected or otherwise

substantially immunocompromised• Contacts with a change in their tuberculin

skin test status from negative to positive• Contacts who might not complete treatment

because of social or behavior impediments

When to Expand a Contact Investigation

Presentingcase

Household/Residence/congregate setting

Leisure/social

medium priority

low priority

high priority

medium priority

high priority

Presenting case

Work/school

When to Expand a Contact Investigation

• Achievement of program objectives with high and medium priority contacts

• Extent of recent transmission

Unexpectedly high rate of infection or TB disease in high priority contacts (e.g. 10% or at least twice the rate of a similar population without recent exposure, whichever is greater)

Evidence of secondary transmission

TB disease in any contact who had been assigned a low priority

Infection of contacts aged <5 years and

Contacts with change of skin test status from negative to positive between their first and second TST

Communicating Through the News Media

Data Management and Evaluation of Contact

Investigations

• Second TST Reminder• Preventive Therapy

Review – high priority contacts not started on Rx

• Contact Progress Reports – 3 & 6 months

• Contact Line Listing• Semi-Annual Report• CDC Contact Report

REPORTS

What, where,

when, ?…

Data Management and Evaluation of Contact Investigations

• Table 4: Index patient minimal recommended data

• Table 5: contact minimal recommended data

• Box 2: Recommended contact investigation objectives by key indicators

• Methods for data collection and storage

Confidentiality and Consent in Contact Investigations

Staffing and Training for Contact Investigations

Staffing and Training for Contact Investigations

Box 3: Specialized functions for contact investigations (e.g. interviewing, case management, etc.)

Box 4: Positions and titles used

Contact Investigations in Special Circumstances

Definition of an Outbreak• During (and because of) a contact

investigation, 2 or more contacts are found to have active TB, regardless of their assigned priority; or

• Any 2 or more cases occurring within a year of each other, discovered to be linked, and the linkage is established outside of a contact investigation

Congregate Settings

• Substantial number of contacts• Incomplete information regarding contact names

and locations• Incomplete data for determining priorities• Difficulty in maintaining confidentiality• Collaboration with officials and administrators

who are unfamiliar with TB• Legal implications• Media coverage

Concerns associated with congregate settings

Correctional Facilities• Establish preexisting formal collaboration

between correctional and public health officials• Trace high-priority contacts who are transferred,

released, or paroled before medical evaluation for TB

• Low completion rate is anticipated unless follow-through

• supervision can be arranged for released or paroled inmates

Workplaces• Duration and proximity of exposure can

be greater than for other settings• Details to gather from index patient

during initial interview include– Employment hours– Working conditions– Workplace contacts

• Occasional customers of workplace should be designated as low priority

Hospitals and Other Health-Care Settings

• Personnel collaborating with hospitals and other health-care agencies should have knowledge of legal requirements

• Plan investigation jointly with health department and setting (division of responsibilities)

• Majority of health-care settings have policies for testing employees for M. tuberculosis infection

Schools

• Early collaboration with school officials and community members is recommended

• Issues of consent, assent, and disclosure of information more complex for minors

• Site visits should be conducted to check indoor spaces, observe general conditions, and interview maintenance personnel regarding ventilation

Shelters and Other Settings Providing Services for Homeless

Persons• Challenges include

– Locating the patient and contacts if mobile

– Episodic incarceration– Migration from one jurisdiction to

another– Psychiatric illnesses– Preexisting medical conditions

• Site visits and interviews are crucial

• Work with setting administrators to offer onsite supervised intermittent treatment

Interjurisdictional Contact Investigations

• Requires joint strategies for finding contacts, having them evaluated, treating infected contacts, and gathering data

• Health department that counts index patient is responsible for leading the investigation and notifying health departments in other jurisdictions

Source-Case Investigations

Child with TB Disease

• Source-case investigations considered for children <5 years of age

• May be started before diagnosis of TB confirmed

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Child with LTBI• Search for source of infection for child is

unlikely to be productive• Recommended only with infected children

<2 years of age, and only if data are monitored to determine the value of the investigation

Cultural Competency and Social Network Analysis

“Every encounter between a health care provider and a patient is a cross-cultural

experience.”

Dr. Arthur Kleinman, Harvard psychiatrist and anthropologist

A Social Network with A Place

Bill

Juan

Rose

TedAli

Moe

Rita

Mel’s Bar

Investigation of Contacts of Persons with Infectious

Tuberculosis, 2005 CHALLENGE: How to fit 50 pages ofNEW recommendationsinto 15 minutes??

5

Investigation of Contacts of Persons with Infectious

Tuberculosis, 2005

Division of Tuberculosis EliminationCenters for Disease Control and Prevention

http://www.cdc.gov/nchstp/tb

National Tuberculosis Controllers AssociationCenters for Disease Control and Prevention