Infection Control:New CDC Guidelines

Kevin Fennelly, MD, MPH

2006 Northeast TB Controllers MeetingRelapse? The State of TB Control in

the Era of Declining Funds

October 24, 2006

Guidelines for Preventing the Transmission of M. tuberculosis in Health-Care Settings, 2005MMWR 2005; 54 (RR-17): 1-147

• health-care-associated outbreaks

• tuberculin skin tests

• airborne infection isolation room

• airborne precautions

• BAMT: Blood assay for M. tuberculosis

– IGRA: interferon gamma release assay

• QFT-G: QuantiFERON-TB Gold test

Guidelines for Preventing the Transmission of M. tuberculosis in Health-Care Facilities, 1994MMWR 1994; 43 (RR-13): 1-132

• nosocomial outbreaks

• PPD (purified protein derivative)

• respiratory isolation room

• TB infection control

New Terminology

What’s New (1)• Change of risk classification and tuberculin

skin test (TST) frequency

• Expanded scope addressing lab, outpatient, and nontraditional settings

• Expanded definitions of affected HCWs

• “TST” instead of “PPD”

Change in Risk Classifications

Previous• Minimal• Very low• Low• Intermediate• High

New• Low• Medium• Potential ongoing

transmission

Please refer to excellent presentation by Philip LoBue at Medical Consultants Meeting, September 20, 2006.

-KF

What’s New (2)

• QuantiFERON-TB Gold test (QFT-G)• QFT-G is a type of blood assay for M.

tuberculosis (BAMT)– Measures the patient’s immune system reaction to

M. tuberculosis– Blood samples must be processed within 12 hours– Interpretation of QFT-G results is influenced by the

patient’s risk for infection with M. tuberculosis– An alternative to TST

TSTs vs. BAMTs for Surveillance of Exposure to Mtb

• TSTs inexpensive assay• Two visits• Cost-effective?• False+s (NTM & BCG)• Allow for historical

comparisons• Two products stable

• Quantitative

• BAMTs expensive: “NIMB”• One visit• Cost-effective?• Eliminates false+s• Uncertainty re: comparing to

TST data• Newer versions will compete &

confuse• Not quantitative: +/-• Lack of technical experience and

new problems– Notice regarding indeterminate

results with the QuantiFERON-TB Gold Test: CDC website, Oct 11, 2006

What’s New (3)

• Term “airborne infection isolation” (AII)• Criteria for initiating and discontinuing AII

precautions• Respirator fit testing and training; voluntary use

of respirators by visitors• Additional information on ultraviolet germicidal

irradiation (UVGI)• Frequently asked questions (FAQs)

Prompt TriageThink TB!

• Primary TB risk to HCWs is patient with undiagnosed or unrecognized infectious TB

• Promptly initiate AII precautions and manage or transfer patients with suspected or confirmed TB– Ask about and evaluate for TB– Check for signs and symptoms– Mask symptomatic patients– Separate immunocompromised patients

This is the Most Important Slide !!!-KF

New Risk Factors for TB: Risk of Transmission ?

• Treatment with immune modulators– Well-documented with TNF-alpha inhibitors– For rheumatoid arthritis & other collagen

vascular diseases, Crohn’s disease, others

• Organ transplantation

• Immune reconstitution inflammatory syndrome (IRIS)

Frequency of Sputum Collection for Patients with Suspected TB

Disease• Three negative sputum smears

• At least 8 hours apart

• At least one collected during early morning

• In most cases, patients with negative sputum smear results may be released from AII in 2 days

Use sputum induction with history of no or scant sputum production ! -- KF

Criteria for Discontinuing AII Precautions

• Infectious TB is unlikely and another diagnosis is made that explains the syndrome

Or• Patient has 3 consecutive negative AFB sputum

smear results, and• Patient has received standard antituberculosis

treatment (minimum of 2 weeks), and• Patient has demonstrated clinical improvement

Discharge to Home• Patient can be discharged without 3 negative

sputum smears if– Follow-up plan has been made with local TB program– Patient is on standard treatment and directly observed

therapy (DOT) is arranged– And clinically improving with microbiological response

(e.g., sputa AFB 4+ to 2 +); low suspicion of MDR-KF– No person in home <4 years old or

immunocompromised *Recommend home visit!*-KF– All in household previously exposed– Patient willing to stay home until sputum results

negative

• Do not release if high-risk persons will be exposed

IC Observations from a Consultant

• Admin: Clinical suspicion for TB among primary care practitioners and specialists is highly variable.

• Environ: Nursing staff need training & know who and when to call, esp in low-use settings.

• PRP: Annual fit-testing is unsupported by data, onerous, costly & detracts from other efforts. – Need coordination within settings: lack of N95s to

which HCWs are fit-tested.– Shortages of N95s due to SARS; expect with

influenza.

Summary

• High index of suspicion remains most important TB IC measure.

• Second most important is effective treatment: micro lab is critical part of IC.

• Environ and PRP controls only work if infectious patients are identified– And if used properly!!

• Key control measure in era of declining funds: EDUCATION!

CDC Tuberculosis Guidelines:Highlights and Controversies 2000-2006

(excerpts related the Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care

Settings, 2005 )

Philip LoBue, MD

Centers for Disease Control and Prevention

Division of Tuberculosis Elimination

September 20, 2006

Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-

Care Settings, 2005 • Published in 2005

• Broadening of scope

• Revision of risk assessment

• Screening of healthcare workers– Allows use of QFT-G in place of TST

Broadening of Scope

• The scope of settings in which the guidelines apply has been broadened to include laboratories and additional outpatient and nontraditional facility-based settings

• Examples– Dentist’s office– Home-based healthcare– Emergency medical services

Health-care Setting Risk Assessment

• Classifications: ongoing transmission, medium risk, low risk

Ongoing Transmission• Evidence of transmission of M. tuberculosis

between patients and/or HCW, occurring in the setting during the preceding year

• Evidence of person-to-person transmission includes– Increased rates or clusters of TST or QFT-G

conversions– HCW with confirmed TB disease– Unrecognized TB disease in patients or HCWs– Recognition of an identical strain of M. tuberculosis in

patients or HCWs with TB disease identified by DNA fingerprinting

Medium and Low Risk

• Medium risk– Inpatient, at least 200 beds: 6 or more TB

patients per year– Inpatient, less than 200 beds; outpatient;

outreach; or home-based healthcare : 3 or more TB patients per year

• Otherwise low risk

TB Screening Procedures for SettingsClassified as Potential Ongoing

Transmission

• Testing for infection with M. tuberculosis might need to be performed every 8–10 weeks until lapses in infection control have been corrected

• “Ongoing transmission” should be used as a temporary classification only

• Warrants immediate investigation and corrective steps

• After a determination that ongoing transmission has ceased, the setting should be reclassified as medium risk for at least 1 year

TB Screening Procedures for Settings Classified as Low Risk

• All HCWs should receive baseline two-step TST or a single QFT-G upon hire

• After baseline testing, additional TB screening is not necessary unless an exposure occurs

• HCWs with a baseline positive or newly positive test or documentation of treatment for LTBI or TB disease should receive a CXR to exclude TB disease

• Routine repeat CXRs are not needed

TB Screening Procedures for Settings Classified as Medium Risk

• All HCWs should receive baseline two-step TST or a single QFT-G upon hire

• After baseline testing, HCWs should receive TB screening annually– Symptom screen for all HCWs– Single TST or QFT-G for HCWs with baseline negative

test results

• HCWs with a baseline positive or newly positive test or documentation of treatment for LTBI or TB disease should receive a CXR to exclude TB disease

• Routine repeat CXRs are not needed

Prevention and Control of Tuberculosis in Correctional and Detention Facilities

• Published in 2006

• Risk assessment – different from health-care settings

• Screening

Risk Assessment• A facility has minimal TB risk if

– No cases of infectious TB have occurred in the facility in the last year

– The facility does not house substantial numbers of inmates with risk factors for TB (e.g., HIV infection and injection-drug use)

– The facility does not house substantial numbers of new immigrants (i.e., persons arriving in the US within the previous 5 years) from areas of the world with high rates of TB

– Employees of the facility are not otherwise at risk for TB

• Any facility that does not meet these criteria should be categorized as a nonminimal TB risk facility

Screening: Minimal Risk Facilities

• All inmates and detainees at intake: screening for symptoms and risk factors for TB

• If no symptoms or risk factors, no further screening required

• If risk factors present: TST or QFT-G or CXR within 7 days of arrival

• If HIV-infected, HIV status unknown with risk factors for HIV, or other severe immunosuppression: CXR

Screening: Nonminimal Risk Facilities

• All inmates and detainees at intake: screening for symptoms AND TST or QFT-G or CXR within 7 days of arrival

• If HIV-infected, HIV status unknown with risk factors for HIV, or other severe immunosuppression: CXR

Additional Evaluation

• If symptoms or abnormal CXR: evaluate for disease

• If TST or QFT-G positive: CXR and evaluate for LTBI treatment once TB disease has been excluded and if completion of treatment is likely