Late boosting phenomenon in TST conversion among health care workers.
Occup Med (Lond)
; 67(6): 484-489, 2017 Aug 01.
Article
in En
| MEDLINE
| ID: mdl-28898965
ABSTRACT
BACKGROUND:
Available information is insufficient to guide determination of whether tuberculin skin test (TST) conversions of health care workers (HCWs) within 2 years of two-step testing are related to occupational exposures or to other causes, including late boosting.AIMS:
To describe the epidemiologic factors of TST conversion in HCWs, comparing early TST conversion (≤2 years after two-step testing) with late conversion to possibly distinguish late boosting phenomenon from occupational TST conversion.METHODS:
Retrospective analysis of a database of TSTs of HCWs from 1 January 1998, through 31 May 2014, in the United States Midwest.RESULTS:
In total, 40142 HCWs had 197932 tests over the 16 years, with 123 conversions (conversion rate 0.3%; 95% CI 0.3-0.4%). Among 61 HCWs with a negative two-step TST, 30 (49%) were found to have early TST conversion within 2 years; 31 (51%) had late conversion, with likely occupational exposure but no identifiable community risks. Persons with early conversion were more likely to be born outside the USA (89% versus 57%; P < 0.05), had a higher rate of prior bacille Calmette-Guérin (BCG) vaccination (89% versus 52%; P < 0.05) and had no identifiable risk factors for conversion (63% versus 58%; P < 0.05).CONCLUSIONS:
Early conversions among HCWs after negative two-step TST are associated with various nonoccupational factors, including international birth and BCG vaccination history. Therefore, conversion is not a reliable indicator of recent tuberculosis contact in this population, and two-step TST is insufficient to discount a delayed boosting response for HCWs.Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Tuberculosis
/
Tuberculin Test
/
Occupational Exposure
/
Health Personnel
Type of study:
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Limits:
Adult
/
Female
/
Humans
/
Male
Country/Region as subject:
America do norte
Language:
En
Journal:
Occup Med (Lond)
Journal subject:
MEDICINA OCUPACIONAL
Year:
2017
Document type:
Article
Affiliation country:
Estados Unidos