Infection Control: New CDC Guidelines

1
Infection ControlNew CDC Guidelines

• Kevin Fennelly, MD, MPH
• 2006 Northeast TB Controllers Meeting
• Relapse? The State of TB Control in the Era of
  Declining Funds
• October 24, 2006

2
New Terminology

• 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

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Whats 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

4
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
5
Whats New (2)

• QuantiFERON-TB Gold test (QFT-G)
• QFT-G is a type of blood assay for M.
  tuberculosis (BAMT)
• Measures the patients immune system reaction to
  M. tuberculosis
• Blood samples must be processed within 12 hours
• Interpretation of QFT-G results is influenced by
  the patients risk for infection with M.
  tuberculosis
• An alternative to TST

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TSTs vs. BAMTs for Surveillance of Exposure to
Mtb

• TSTs inexpensive assay
• Two visits
• Cost-effective?
• Falses (NTM BCG)
• Allow for historical comparisons
• Two products stable
• Quantitative

• BAMTs expensive NIMB
• One visit
• Cost-effective?
• Eliminates falses
• 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

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Whats 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)

8
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
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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, Crohns disease, others
• Organ transplantation
• Immune reconstitution inflammatory syndrome (IRIS)

10
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
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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

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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 lt4 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

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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.

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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!

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CDC Tuberculosis GuidelinesHighlights 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

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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

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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
• Dentists office
• Home-based healthcare
• Emergency medical services

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Health-care Setting Risk Assessment

• Classifications ongoing transmission, medium
  risk, low risk

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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

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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

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TB Screening Procedures for SettingsClassified
as Potential Ongoing Transmission

• Testing for infection with M. tuberculosis might
  need to be performed every 810 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

22
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

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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

24
Prevention and Control of Tuberculosis in
Correctional and Detention Facilities

• Published in 2006
• Risk assessment different from health-care
  settings
• Screening

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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

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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

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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

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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