Late boosting phenomenon in TST conversion among health care workers.

摘要: Background Available information is insufficient to guide determination of whether tuberculin skin test (TST) conversions health care workers (HCWs) within 2 years two-step testing are related occupational exposures or other causes, including late boosting. Aims To describe the epidemiologic factors TST conversion in HCWs, comparing early (≤2 after testing) with possibly distinguish boosting phenomenon from conversion. Methods Retrospective analysis a database TSTs HCWs 1 January 1998, through 31 May 2014, United States Midwest. Results In total, 40142 had 197932 tests over 16 years, 123 (conversion rate: 0.3%; 95% CI 0.3-0.4%). Among 61 negative TST, 30 (49%) were found have years; (51%) conversion, likely exposure but no identifiable community risks. Persons more be born outside USA (89% versus 57%; P < 0.05), higher rate prior bacille Calmette-Guerin (BCG) vaccination 52%; 0.05) and risk for (63% 58%; 0.05). Conclusions Early among associated various nonoccupational factors, international birth BCG history. Therefore, not reliable indicator recent tuberculosis contact this population, discount delayed response HCWs.