Post-trial perceptions of a symptom-based TB screening intervention in South Africa: implementation insights and future directions for TB preventive healthcare services.

BACKGROUND: Tuberculosis is a top-10 cause of under-5 mortality, despite policies promoting tuberculosis preventive therapy (TPT). We previously conducted a cluster randomized trial to evaluate the effectiveness of symptom-based versus tuberculin skin-based screening on child TPT uptake. Symptom-based screening did not improve TPT uptake and nearly two-thirds of child contacts were not identified or not linked to care. Here we qualitatively explored healthcare provider perceptions of factors that impacted TPT uptake among child contacts. METHODS: Sixteen in-depth interviews were conducted with key informants including healthcare providers and administrators who participated in the trial in Matlosana, South Africa. The participants' experience with symptom-based screening, study implementation strategies, and ongoing challenges with child contact identification and linkage to care were explored. Interviews were systematically coded and thematic content analysis was conducted. RESULTS: Participants' had mixed opinions about symptom-based screening and high acceptability of the study implementation strategies. A key barrier to optimizing child contact screening and evaluation was the supervision and training of community health workers. CONCLUSIONS: Symptom screening is a simple and effective strategy to evaluate child contacts, but additional pediatric training is needed to provide comfort with decision making. New clinic-based child contact files were highly valued by providers who continued to use them after trial completion. Future interventions to improve child contact management will need to address how to best utilize community health workers in identifying and linking child contacts to care. TRIAL REGISTRATION: The results presented here were from research related to NCT03074799 , retrospectively registered on 9 March 2017.

Improving Tuberculosis Preventive Therapy Uptake: A Cluster-randomized Trial of Symptom-based Versus Tuberculin Skin Test-based Screening of Household Tuberculosis Contacts Less Than 5 Years of Age.

BACKGROUND: Tuberculosis preventive therapy (TPT) is highly effective at preventing tuberculosis disease in household child contacts (<5 years), but is poorly implemented worldwide. In 2006, the World Health Organization recommended symptom-based screening as a replacement for tuberculin skin testing (TST) to simplify contact evaluation and improve implementation. We aimed to determine the effectiveness of this recommendation. METHODS: We conducted a pragmatic, cluster-randomized trial to determine whether contact evaluation using symptom screening improved the proportion of identified child contacts who initiated TPT, compared to TST-based screening, in Matlosana, South Africa. We randomized 16 clinics to either symptom-based or TST-based contact evaluations. Outcome data were abstracted from customized child contact management files. RESULTS: Contact tracing identified 550 and 467 child contacts in the symptom and TST arms, respectively (0.39 vs 0.32 per case, respectively; P = .27). There was no significant difference by arm in the adjusted proportion of identified child contacts who were screened (52% in symptom arm vs 60% in TST arm; P = .39). The adjusted proportion of identified child contacts who initiated TPT or tuberculosis treatment was 51.5% in the symptom clinics and 57.1% in the TST clinics (difference -5.6%, 95% confidence interval -23.7 to 12.6; P = .52). Based on the district's historic average of 0.7 child contacts per index case, 14% and 15% of child contacts completed 6 months of TPT in the symptom and TST arms, respectively (P = .89). CONCLUSIONS: Symptom-based screening did not improve the proportion of identified child contacts evaluated or initiated on TPT, compared to TST-based screening. Further research is needed to identify bottlenecks and evaluate interventions to ensure all child contacts receive TPT. CLINICAL TRIALS REGISTRATION: NCT03074799.

Weekly rifapentine/isoniazid or daily rifampin/pyrazinamide for latent tuberculosis in household contacts.

RATIONALE: Treatment of latent tuberculosis (TB) infection with weekly rifapentine and isoniazid is a potentially effective alternative to current therapies. OBJECTIVES: To compare the efficacy of weekly rifapentine/isoniazid to daily rifampin/pyrazinamide in preventing TB in household contacts of patients with pulmonary TB in Brazil. METHODS: Contacts of patients with TB were randomized to rifapentine 900 mg/isoniazid 900 mg once weekly for 12 wk or rifampin 450-600 mg/pyrazinamide 750-1,500 mg daily for 8 wk and followed for at least 2 yr. MEASUREMENTS: TB rates, adverse events, and adherence to therapy. MAIN RESULTS: A total of 399 household contacts were enrolled, 206 in the rifapentine/isoniazid arm and 193 in the rifampin/pyrazinamide arm. The median age was 34 yr, median weight was 63 kg, 60% of participants were female, and only one patient was HIV infected. Rifapentine/isoniazid was well tolerated, but the trial was halted by the investigators before completion because of unanticipated hepatotoxicity in the rifampin/pyrazinamide arm. Twenty of 193 participants (10%) receiving rifampin/pyrazinamide experienced grade 3 or 4 hepatotoxicity, compared with 2 of 206 participants (1%) on rifapentine/isoniazid (p<0.001). There were no hospitalizations or deaths due to hepatotoxicity, and all participants' liver enzyme levels returned to normal during follow-up. During follow-up, four cases of active TB developed, three in the rifapentine/isoniazid group and one in the rifampin/pyrazinamide group (1.46 vs. 0.52%; difference, 0.94%; 95% confidence interval, -1.6 to 3.7%). CONCLUSIONS: Rifapentine/isoniazid was better tolerated than rifampin/pyrazinamide and was associated with good protection against TB. Rifapentine/isoniazid weekly for 12 wk is likely a promising therapy for latent TB infection.

Evaluation of a whole-blood interferon-gamma release assay for the detection of Mycobacterium tuberculosis infection in 2 study populations.

A whole-blood interferon-gamma release assay (IGRA) is being evaluated for its potential to replace the tuberculin skin test (TST) for detecting Mycobacterium tuberculosis infection. To test the assay in a population in which tuberculosis is highly endemic and in another population that is representative of an urban United States population, 253 volunteers from Ethiopia and 175 volunteers from Baltimore were studied for responsiveness on IGRA compared with a simultaneously performed TST. The agreement between the 2 tests, beyond that due to chance, was 68% among subjects from Baltimore and only 35% among those from Ethiopia. IGRA had a sensitivity of 71%, compared with 95% sensitivity for the TST, among 21 subjects who had undergone treatment for culture-confirmed tuberculosis. The specificity was 85% for IGRA and 96% for TST among 52 subjects with no known history of exposure to tuberculosis. In its current form, with purified protein derivative used as the stimulation antigen, the IGRA was found to perform poorly in comparison to the TST in diagnosing M. tuberculosis infection.