In a widely anticipated move, the CDC has dropped routine annual tuberculosis testing of healthcare workers in the absence of an exposure or ongoing transmission.

“Overall, this is going to save time and money for everybody,” says lead author Lynn Sosa, MD, TB/STD Control Programs Coordinator at the Connecticut Department of Public Health.

The CDC screening change, an update to the agency’s 2005 TB guidelines, was expected as the disease continues to decline nationwide and healthcare workers appear to be at no greater risk of transmission than the general public. (For more information, see the April 2019 issue of HEH.)

“In addition, a recent retrospective cohort study of approximately 40,000 healthcare personnel at a tertiary U.S. medical center in a low TB-incidence state found an extremely low rate of TST [tuberculin skin test] conversion (0.3%) during 1998-2014, with a limited proportion attributable to occupational exposure,” the CDC reported.1,2

Routine annual screening in such low-risk populations has little epidemiological value and could even trigger false positives and unnecessary anxiety in healthcare workers.

“The goal really is to decrease the amount of annual testing that is being done,” Sosa says. “The recommendation is a lot more strongly stated that we really don’t need to be doing annual testing in almost every situation. This will save time because now you are not focused on tracking down people to get them tested every year.”

Building On Prior Success

There also is a new emphasis on getting healthcare workers on effective TB treatment if they do have latent disease.

“That will save money because we will have less contact investigations because we are going to treat people before they get sick,” Sosa says.

The caveat is that employee health professionals must continue to emphasize the factors that made this success possible, including rapid identification of TB patients, isolation, and workers donning respirators to care for them.

“The 2005 recommendations3 still stand in terms of the infection control and the environmental control recommendations,” Sosa says. “Those are still really important. Just doing a test on healthcare workers does not prevent TB transmission.”

Risk Assessment

As part of the an initial “preplacement” TB test for healthcare workers, the CDC recommends an individual risk assessment. Healthcare workers should be considered at increased risk for TB if they answer ‘yes’ to any one of the following statements:

  • Residence for a month or more in a country with a high TB rate (i.e., any country other than Australia, Canada, New Zealand, the United States, and those in western or northern Europe);
  • Workers with suppressed immune systems, including from HIV, organ transplant, treatment with a tumor necrosis factor (TNF)-alpha antagonist (e.g., infliximab, etanercept, or other), chronic steroids (equivalent of prednisone ≥15 mg/day for ≥1 month), or other immunosuppressive medication;
  • Close contact with an infectious TB patient since the last TB test.1

“Instead of looking at the risk of a particular facility, we are focused on the risk of the individual person working in the healthcare setting,” Sosa says. “Because it really is important to understand what that individual’s risk of TB is to interpret and better understand the test results.”

For example, the first question dealing with geography could pick up healthcare workers who may have been exposed to TB in other countries or those administered the Bacillus Calmette–Guérin (BCG) TB vaccine, which is not routinely used in the U.S. Those vaccinated may experience a cross-reaction to a TB skin test, registering a false positive. There was some speculation that the CDC would emphasize blood tests over skin tests in the guidelines, but the agency takes a neutral position.

“There are other recommendations in regard to using skin tests vs. blood tests, so this [guideline] was not really the place to favor one over the other,” Sosa says.

“We refer to the 2017 guidelines4 which go into detail when a skin test or a blood test might be preferred. There are also other reasons healthcare facilities may choose one test over the other in terms of costs and things like that, so we did not want to say ‘you have to use one or the other.’”

If healthcare workers test positive for latent TB infection, the new guidelines emphasize treatment to avoid onset of active disease in the future.

“If we can identify healthcare personnel and get them treated, that is also going to continue to decrease the amount of TB that is in healthcare settings,” she says. “If those healthcare workers are treated, then there is no chance of them getting sick and giving TB to their patients, colleagues, family, and friends.”

Improved treatment options are one reason for the greater emphasis on this recommendation since 2005, when the primary therapy was nine months of isoniazid. Now, options include four months of rifampin or 12 weeks of a combination of isoniazid and rifapentine given once a week, Sosa says.

“If we want to continue to drive TB down, we have to treat the reservoir of future disease,” she says. “This is all in line with what we are doing nationally, which is going to help us eventually get rid of TB in the U.S.”

To reiterate and summarize, the new CDC guidelines recommend the following:

  • “TB screening with an individual risk assessment and symptom evaluation at baseline (preplacement);
  • “TB testing with an interferon-gamma release assay (IGRA) or a tuberculin skin test (TST) for persons without documented prior TB disease or latent TB infection (LTBI);
  • “No routine serial TB testing at any interval after baseline in the absence of a known exposure or ongoing transmission;
  • “Encouragement of treatment of all healthcare personnel with untreated LTBI, unless treatment is contraindicated;
  • “Annual symptom screening for healthcare personnel with untreated LTBI;
  • “Annual TB education of all healthcare personnel.”1

REFERENCES

  1. Sosa LE, Njie GJ, Lobato MN, et al. Tuberculosis Screening, Testing, and Treatment of U.S. Health Care Personnel: Recommendations from the National Tuberculosis Controllers Association and CDC, 2019. MMWR 2019;68(19):439–443.
  2. Dobler CC, Farah WH, Alsawas M, et al. Tuberculin skin test conversions and occupational exposure risk in US healthcare workers. Clin Infect Dis 2018;66:706–711.
  3. Jensen PA, Lambert LA, Lademarco MF, et al. Guidelines for preventing the transmission of Mycobacterium tuberculosis in health-care settings, 2005. MMWR 2005;54(No. RR-17).
  4. Lewinsohn DM, Leonard MK, LoBue PA, et al. Official American Thoracic Society/Infectious Diseases Society of America/Centers for Disease Control and Prevention clinical practice guidelines: diagnosis of tuberculosis in adults and children. Clin Infect Dis 2017;64:111–115.