Annual TB rates in the United States have declined substantially during the past nearly three decades, according to CDC data, with the 2017 rate dipping to 2.8 per 100,000 population -- a 73% decrease from 1991, when the rate was 10.4 per 100,000, and a 42% dip from 2005's rate of 4.8 per 100,000.
Mycobacterium tuberculosis, a pathogenic bacterial species in the family Mycobacteriaceae, is by far the most common cause of TB. However, M. africanum and M. bovis can also cause TB disease in humans.
Additionally, surveillance data reported to the agency from 1995 to 2007 showed that TB incidence rates among health care personnel were similar to those in the general population, raising questions about the cost-effectiveness of routine serial occupational testing.
Furthermore, a recent retrospective cohort study(academic.oup.com) of about 40,000 health care workers at a tertiary U.S. medical center in a low TB-incidence state found an extremely low rate of tuberculin skin test conversion (0.3%) during 1998-2014, with only a limited proportion attributed to occupational exposure.
Finally, previous research(thorax.bmj.com) has suggested that interferon-gamma release assays and TSTs are limited in their ability to serially test health care personnel who are at low risk for latent TB infection and the disease.
These collective findings led the CDC to update its "Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Health-Care Settings, 2005."(www.cdc.gov) The new guidance was published in a Morbidity and Mortality Weekly Report(www.cdc.gov) released May 17.
The agency based its update on evidence from a systematic review conducted by a National Tuberculosis Controllers Association/CDC work group using methods adapted from the Guide to Community Preventive Services.(www.thecommunityguide.org)
In addition, the draft NTCA/CDC recommendations were presented publicly at the April 2018 meeting of the Advisory Council for the Elimination of Tuberculosis and the May 2018 meeting of the Healthcare Infection Control Practices Advisory Committee for feedback from the groups' members. The CDC incorporated these comments into its updated recommendations.
The work group also requested that NTCA convene a new work group to develop supplemental implementation guidance to aid health care facilities in implementing the updated recommendations, a concept both ACET and HICPAC supported; that document is expected to be completed later this year, the MMWR said.
The updated health care personnel recommendations now call for
- baseline (preplacement) TB screening with an individual risk assessment and symptom evaluation at baseline for all personnel;
- TB testing with an IGRA or a TST for personnel who have a known exposure to TB and who have no documented prior TB disease or LTBI;
- no routine serial TB testing at any interval after baseline in the absence of a known exposure or ongoing transmission;
- symptom evaluation and chest radiograph for all personnel with a newly positive test result, with followup as indicated;
- encouraging treatment for all personnel with untreated LTBI, unless treatment is contraindicated;
- annual symptom screening for personnel with untreated LTBI; and
- annual TB education for all health care personnel.
Recommendations from the 2005 CDC guidelines that were deemed to be outside the scope of health care personnel screening, testing, treatment and education -- such as those addressing facility risk assessments and infection-control practices -- remain unchanged.
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