Infection Control:
New 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
New Terminology
Guidelines for Preventing the
Transmission of M. tuberculosis in
Health-Care Settings, 2005
MMWR 2005; 54 (RR-17): 1-147
•
health-care-associated outbreaks
Guidelines for Preventing the
Transmission of M. tuberculosis in
Health-Care Facilities, 1994
MMWR 1994; 43 (RR-13): 1-132
•
nosocomial outbreaks
• tuberculin skin tests
• PPD (purified protein derivative)
• airborne infection isolation room
• respiratory isolation room
• airborne precautions
• TB infection control
• BAMT:
Blood assay for M.
tuberculosis
– IGRA: interferon gamma
release assay
• QFT-G: QuantiFERON-TB
Gold test
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
New
•
•
•
•
•
• Low
• Medium
• Potential ongoing
transmission
Minimal
Very low
Low
Intermediate
High
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 QuantiFERONTB 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 Triage
Think 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 HealthCare 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 facilitybased 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 Settings
Classified 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 healthcare 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