Vigilance: TB prevention remains a priority
ACOEM urges steps to reduce risk
With historically low rates of tuberculosis in the United States and ongoing challenges with TB tests, employee health professionals are understandably frustrated. But the American College of Occupational and Environmental Medicine (ACOEM) has a message: Remain vigilant to prevent occupational risk.
In recently released guidance, ACOEM notes that the high worldwide rate of latent TB infection and rising rates of multi-drug resistant and extensively drug-resistant TB pose a risk to health care workers.
In fact, in the 1980s and early 1990s a resurgence of TB combined with less stringent infection control measures led to some hospital-based transmission of TB, ACOEM notes.
"If we don't keep up the scrutiny and assign resources to TB screening of health care workers, we could easily slip back," says Amy J. Behrman, MD, FACP, FACOEM, medical director for Occupational Medicine at the University of Pennsylvania Health System and lead author of the ACOEM guidance. "We should build on our successes and not be complacent about the ongoing risk."
ACOEM emphasizes important "action steps" to reduce the risk of TB exposure, including having a high level of suspicion of TB in patients with cough and fever who have risk factors, such as the homeless, incarcerated, or those from countries in which TB is endemic. Patients suspected of having active TB should wear a mask when not in an isolation room, and health care workers who have contact with them should wear respiratory protection, ACOEM says.
In the guidance, ACOEM notes that powered air-purifying respirators (PAPRs) may provide more protection than an N95, and that the quality of the N95 affects its fit.
As for the complex issues involved with TB screening of health care workers, ACOEM suggests retesting those with interferon gamma release assay (IGRA) results near the cut point (or between .35 and 1.1 IU/mL for the QuantiFERON test). (See related article, cover.)
"For positive IGRA results, there is accumulating evidence that the current Food and Drug Administration approved threshold for a positive test may not be accurate," ACOEM said.
The Centers for Disease Control and Prevention states that in some cases using both a tuberculin skin test and IGRA might be appropriate,1 and the ACOEM guidance acknowledges this reality: "Neither IGRAs nor TSTs alone can be considered definitive proof of infection. Many physicians currently use both TST and IGRA in combination to manage LTBI surveillance and treatment."
For example, some institutions use IGRAs to confirm a positive TST, particularly in people who received BCG vaccination as children, Behrman notes.
ACOEM will continue to update guidance as new information emerges, especially related to the screening tests, she says. "Continued attention to this is the way to continue to achieve historic lows in [TB] case rates and transmission," she says.
[Editor's note: The ACOEM guidance statement, Protecting Health Care Workers From Tuberculosis, 2013, is available at www.acoem.org/Guidance_Statements.aspx.]
- Centers for Disease Control and Prevention. Updated guidelines for using interferon gamma release assays to detect Mycobacterium tuberculosis—United States, 2010. MMWR 2010; 59:125.