TB Contact Investigation

Transcription

1 Ann Raftery, RN, PHN, MS Curry International TB Center Overview Contact investigation as a core TB control and elimination activity Components of TB Contact Investigation TB Control Priority Strategies. Prompt detection, reporting and treatment of persons with active TB. Identification and evaluation of contacts of persons with contagious TB 3. Targeted testing and treatment of persons with latent TB infection 4. Strengthening infection control measures in settings at high risk for TB transmission

2 Why? Find active TB cases: treat and prevent ongoing transmission Find persons with TB infection: treat and prevent future cases Process. Collect and evaluate index case information: Decide whether to initiate a contact investigation. Investigate index case & sites of transmission 3. Prioritize contacts 3 4. Locate & evaluate contacts 5. Treatment & follow-up of contacts 6. Decide whether to expand the investigation 7. Data management & evaluation of contact investigation activities 4 Step : Collect and Evaluate Index Case Information: Decide whether to initiate a Contact Investigation

3 What Information is Collected? Background information regarding the patient and circumstances of the illness: Demographics, identifiers and locating information TB Information: site of disease; regimen and start date(s); history of previous TB exposure, disease, treatment ; TB symptoms and the onset date(s) Results of diagnostic tests Medical conditions Important social factors 7 Assessing Transmission Risk TB CASE FACTORS Site of TB Disease LIKELIHOOD OF DISEASE TRANSMISSION MORE LIKELY Laryngeal / pulmonary or pleural LOWER LIKELIHOOD Extra pulmonary alone Smear status Positive Negative Chest X ray Cavitation Non cavitary Symptoms/ behaviors Coughing, singing, sneezing, sociability Not coughing, singing, sneezing Age Adult or adolescent Child <0 years of age Anti TB drugs No or ineffective Rx Yes ( weeks or more) 8 Initiate a Contact Investigation? Index Case TB Classification TB 3: Culture + Pulmonary, laryngeal or pleural TB TB 5: High Pulmonary, laryngeal or pleural TB and TB treatment initiated TB 5: Low Pulmonary, laryngeal or pleural TB and TB treatment not initiated TB 3 or 5: EPTB No pulmonary laryngeal or pleural involvement Always Always TB3= Active TB case; TB5= Suspect case C+ C- Not indicated Always Not indicated 3

4 Step : Investigate Index Case and Sites of Transmission Step a: Investigate Index Case Review case information Medical & other health records Step a: Investigate Index Case () Interview the TB patient (index case) to gather information to: Help estimate onset of the infectious period Identify contacts & locating information Identify sites where transmission may have occurred 4

5 Estimating the Beginning of the Infectious Period TB Classification TB3: Cult + pulmonary, laryngeal or pleural TB TB5/High: (culture pending) TB Rx started TB5/Low: (culture pending) No TB treatment Index Case Characteristics Either AFB S+, Cavitary chest X-ray, or TB symptoms All of the following: AFB S -; CXR abnormal (not cavitary); and no TB symptoms Either AFB S+, Cavitary chest X-ray, or TB symptoms All of the following: AFB smears, NAAT or MB neg. or ND; CXR abnormal (not cavitary); and no TB symptoms When respiratory specimens are subsequently found to be culturepositive for M.tb Minimal recommendation for beginning of the likely period of infectiousness 3 months before symptom onset or st positive finding consistent with TB disease, whichever is longer 4 weeks prior to date of diagnosis as a confirmed case 3 months before symptom onset or st positive finding consistent with TB disease, whichever is longer 4 weeks prior to date of diagnosis as a TB suspect Follow guideline for TB3: Cult+ Closing the Infectious Period Infectious period closed when ALL the following criteria are met: Effective treatment for weeks Diminished symptoms Mycobacteriologic response (e.g., number AFB seen on smear microscopy) 4 Step b: Examine Sites of Transmission (Field Investigation) Visit the sites where the patient spent time during infectious period Components include: Assess physical conditions of the setting Interview, arrange for evaluation & provide TB information to contacts Identify additional contacts 5 5

6 Step p3: Prioritize Contacts Assign Priority Level to each Contact Contact Roster High Priority 3-5 business days to initial encounter Medium Priority 4 business days Low Priority Non-contact How to Prioritize Contacts Consider both: Factors associated with transmission Factors associated with increased risk for progression to TB disease (vulnerability) 8 6

7 When assigning priority, consider: Infectiousness of the TB case Circumstances of the exposure Environment where transmission likely occurred Frequency & duration of exposure Infectiousness Exposure Susceptibility/vulnerability intensity Susceptibility factors of the contact Age, immune suppressed, other medical risk factors Any contact with TB symptoms = High priority 9 High Priority Contacts High Priority Contacts are:. Most likely to be infected. Most likely to progress to disease if infected 3. Most likely to suffer increased morbidity or mortality from TB disease 0 Step p4: Locate and Evaluate Contacts 7

8 Locating Contacts Consider: Social networks Re-interviews Jails, shelters DMV; Postal service CDPH Patient Locating Service (see Fact Sheet for contact info.) Evaluating Contacts Tuberculin skin test (TST)/IGRA initial; then 8-0 weeks post contact Review of symptoms Medical & TB history Chest X-ray Sputum for AFB smear & culture (request for rapid drug resistance testing if exposure to a known MDR/XDR case) Evaluation: Special Contact Groups Child < 5 y/o or immunocompromised: Medical history Physical exam Chest X-ray y( (PA & lateral views) Tuberculin skin test Documented prior positive TST or IGRA: Obtain medical and exposure history Obtain prior treatment history If treatment for LTBI is indicated, obtain CXR prior to treatment initiation 8

9 Step p5: Treatment and Follow-up of Contacts Treatment & Follow-up of Contacts Prioritize efforts with contacts who are most in need of treatment Monitor throughout treatment (monthly face-to- face) Window-period prophylaxis TST-negative high-risk contacts during the period following last contact until the follow-up TST (8-0 weeks after last contact) MDR-TB exposure seek expert consultation; follow-up years post exposure Step 6: Decide Whether to Expand the Investigation 9

10 When should investigation be expanded? Consider both of the following: Program objectives with high and medium priority contacts have been achieved AND There is evidence of recent transmission 8 Evidence of Recent Transmission Unexpectedly high rate of infection or disease in high priority contacts Infection in a young child (< 5 yr. old) TST/IGRA conversion (from negative st test to positive nd test) Secondary case TB disease in any contact assigned a low priority 9 Step p7: Data Management and Evaluation of Contact Investigation Activities 0

11 Step 7: Data Management & Evaluation of C.I. Activities Management of care & follow up of TB case & contacts Epidemiologic analysis of the investigation in progress to allow prioritization of program activities & resources Program evaluation measure how well objectives are being met 3 Summary Contact investigation is a priority public health intervention Active case finding Opportunity to prevent ongoing transmission and future cases Keep focus on high and medium priority contacts California guidelines available at: