Association Between Staff Experience and Effective Tuberculosis Contact Tracing in North Carolina, 2008-2009

Effective investigation of tuberculosis (TB) contacts is essential for continued progress toward TB elimination. As the incidence of TB declines, staff experience will also decline. Little is known about the association between the experience level of public health TB staff and the quality of contact investigations.

Contact investigations involving fewer than 30 contacts during the period 2008-2009 were included in this analysis. Multivariable models were used to examine associations between staff TB experience (assessed by a standardized survey) and measures of contact investigation quality: time from case identification to contact identification and number of contacts identified per case investigated.

A total of 501 cases and 3,230 contacts met the inclusion criteria. Data were stratified by the number of cases in the county and whether the case was smear-positive or smear-negative. For contacts of smear-positive cases, greater staff experience was associated with more rapid contact identification both in counties with high case counts (hazard ratio [HR] = 2.43; 95% CI, 1.79-3.31) and in counties with low case counts (HR = 1.142; 95% CI, 0.95-1.37). However, for smear-negative cases, staff in counties with low case counts identified contacts more slowly as years of experience increased (HR = 0.82; 95% CI, 0.62-1.07). For contacts of smear-negative cases, more contacts (relative risk [RR] = 1.20; 95% CI, 1.07-1.35) were identified per case in high case-count counties (more than 20 cases during 2008-2009). Conversely, in low case-count counties, fewer contacts were identified per case (RR = 0.94; 95% CI, 0.82-1.08); however, this finding was not significant.

Speed of identification and number of contacts are imperfect surrogates for the most important outcome of contact investigations-that is, the rapid identification and treatment of infected contacts.

More TB experience was associated with more rapid and thorough TB contact investigations. Retaining experienced staff and mentoring staff new to case management should be high priorities for TB control programs.