Evaluation of a School-Based Tuberculosis-Screening Program and Associate Investigation Targeting Recently Immigrated Children in a Low-Burden Country

Abstract

CONTEXT. In countries with a low incidence of tuberculosis (TB), screening programs targeting recent immigrants from TB-endemic countries have been shown to be effective in further reducing TB incidence; however, evaluative data on some aspects of these programs remain sparse.OBJECTIVE. We sought to retrospectively evaluate a school-based screening program targeting children at high risk for TB infection in Montreal, Canada, as well as subsequently investigate family and household associates of the schoolchildren with latent TB infection (LTBI), based on adherence to LTBI therapy and costbenefit analysis.DESIGN, SETTING, AND PARTICIPANTS. Newly arrived immigrant children (aged 4 -18 years) in selected schools were screened for LTBI by using the tuberculin skin test (TST). The TST was defined as positive at an induration of Ն10 mm. Each child who tested positive on the TST was referred for medical evaluation. Family and household associates of the TST-positive child also were screened for LTBI. Classroom attendance sheets and medical charts were reviewed for 16 elementary and secondary schools that comprised the school-screening program of the Montreal Children's Hospital from 1998 to 2003. Medical charts of the child associates (Ͻ18 years old) who were screened were reviewed also.MAIN OUTCOME MEASURES. The main outcome measures were TST-positivity rate, rate of adherence to LTBI therapy, estimation of factors associated with adherence, and net cost/benefit of the school-screening and associate-investigation programs, both respectively and as a combined program, compared with the cost of passive treatment of TB disease.RESULTS. Of 2524 immigrant children screened, 542 (21%) were TST-positive. Of 342 children started on therapy, 316 (92%) demonstrated adequate adherence. The only predictor of adherence among the schoolchildren was having Ն2 family members brought in for TB screening (adjusted odds ratio: 2.0; 95% confidence interval: 1.3-3.3). There were 599 associates investigated from the 484 TST-positive schoolchildren seen at the TB clinic. Of 555 associates with TST results, 211 (38%) were found to be TST-positive. Of 136 TST-positive child associates, 131 were seen at the Montreal Children's Hospital TB clinic and had their chart reviewed. Of these, 108 (82%) were started on LTBI therapy, and 78 (79%) of 99 of those children with information complied adequately with their therapy. We found net benefits from both school-based screening and associate investigation, both as stand-alone programs and as 1 coordinated, targeted TB-screening program.CONCLUSION. We demonstrated the effectiveness, including cost-effectiveness, of a targeted, school-based screening program in a low-burden country and the extra benefit given by adding associates to such a program. IMMIGRANTS AND FOREIGN-BORN Canadians account for more than half of all active tuberculosis (TB) cases in Canada, 1 and in Montreal their overall risk for developing active disease is 10 times higher than the nonforeign-born population (37.5 and 3.3 c...

Evaluation of a school-based program for diagnosis and treatment of latent tuberculosis infection in immigrant children

“…Our targeted school-based screening program achieved a TST positivity rate of 22.8% and good compliance in 61.8%, therefore fulfilling these criteria. Our rate of LTBI was identical to other school-based series [8,15], but, with better case selection, it could have been improved. We chose to target at-risk classrooms rather than at-risk children [7] in order to rapidly test a large number of children.…”

“…In previous studies, it varied from 20 to 27.6% in south African children <5 years [13,14], to 56.8% in Israelis 12-13 years old [10], 50-80% in foreign-born adolescents living in the United States [11,12] and 82-92% in children recently immigrating to Canada [8,9,15]. Our lower rate of treatment completion compared to other Canadian series can be explained by our rigid definition for adequate adherence: children taking >80% of the total dose within 120% of the allotted time.…”

“…The threshold of 80% of the dose is commonly chosen for good adherence [18]. As others [15], we have added limits in the duration of treatment to include children that had taken all the doses in a slightly longer time. However, when it took a very long time (>120% of the planned duration) to assess ≥80% of the prescribed doses, children were considered poor compliant.…”

“…As adherence is challenging in pediatric LTBI treatment [8][9][10][11][12][13][14][15], we tried to identify factors contributing to acceptance and to completion of treatment.…”

A Systematic Review on TST and IGRA Tests Used for Diagnosis of LTBI in Immigrants

“…Of the 51 studies included in our review, 32 were ranked high quality [23-41, 57-61, 66-73] and 19 were ranked acceptable quality [42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][62][63][64][65]. Across the 51 studies, 34 studies looked at TST alone and 9 studies looked at IGRAs alone [57][58][59][60][61][62][63][64][65]; 8 studies compared TST and IGRAs [66][67][68][69][70][71][72][73].…”