Tuberculin skin testing among health care workers in a country with a high tuberculosis prevalence: booster and conversion rates

Abstract number: p1104

Hizel  K., Ozer  F., Maral  I., Aktas  F.

Objective: 

To determine tuberculin skin test (TST) survey and conversion rates among health care workers (HCWs) of a teaching hospital in Turkey. Thus, to assess whether HCWs are at increased risk for tuberculosis (TB) in a country with a high prevalence and universal BCG vaccination. The effect of previous BCG vaccination on the result of TST was also investigated.

Method: 

In 2001, two-step TST was administered to consenting HCWs of the hospital. All participants completed a standard questionnaire regarding demographic data including age, gender, workplace, occupation, previous BCG vaccination and history of exposure to tuberculosis. In 2003, TST was reapplied to HCWs with negative reaction after the two-step test.

Results: 

Of the 513 participants, 364 (70.9%) had a positive TST reaction on initial testing. A higher prevalence of positive TST reaction was found among participants working in the surgical ward (79.9%; OR 2.58; 95% CI 1.50–4.44) than in the medical ward (69.1%), and nurses (75.5%; OR 2.15; 95% CI 1.14–4.06) than clerks (71%), receptionist (68.8%), and administrative personnel (58.9%). Presence of BCG scar was not significantly associated with positive TST response. Among 114 employees with a negative TST reaction who underwent a second test, the booster reaction was found in 12 (10.5%). In 2003, conversion was found in 10 (16.3%) of 61 participants. Conversion was not significantly associated with any of the variables examined.

Conclusion: 

In high TB prevalence countries, HCWs are increased risk for the infection. The effect of previous BCG vaccination on the result of TST was minimal, and positive response to TST was related to natural infection rather than previous vaccination. Our study supports the CDC recommendations, which emphasize that screening of HCWs with TST is beneficial to evaluate TB exposure and is suitable for high TB prevalence countries too.