Characteristics of contact persons.

The World Health Organization recommends TB contact investigation in high-burden countries. We examined the implementation reach of two contact investigation strategies in South Africa. Kharitode TB, a cluster-randomized crossover trial, compared household- and incentive-based contact investigation in 28 clinics (July 2016-January 2020). Clinics used each strategy for 18 months (separated by a six-month “washout”). Adults recently diagnosed with TB (index participants) were enrolled. In the household-based arm, contact persons were screened and provided sputum samples at home. In the incentive-based arm, index participants distributed referral coupons to their contacts, who received a $3.50 incentive upon presenting for screening at clinics. We used mixed-effects logistic regression with random intercepts for clinics to examine factors associated with index participant enrollment and sputum collection from contact persons. In the household-based arm, 782/1,269 (61.6%) index participants consented, 1,882 contact persons were enrolled and sputum samples were collected from 988/1,882 (52.5%). In the incentive-based arm, 780/1,295 (60.2%) index participants consented, 1,940 contact persons were enrolled and sputum was collected from 1,431/1,940 (73.8%). Index participants living with HIV (adjusted odds ratio, aOR=0.56, 95% CI 0.38-0.83) or unknown HIV status (aOR=0.12, 95% CI 0.07-0.20) were less likely to participate in the study. Contact persons in the incentive-based arm were more likely to provide a sputum sample compared to those in the household-based arm (aOR=2.12, 95% CI 1.80-2.50). Regardless of the study arm, cough (aOR=2.27, 95% CI 1.87-2.77), current smoking (aOR=2.22, 95% CI 1.63-3.02), and living with HIV (aOR=1.89, 95% CI 1.36-3.62) were associated with higher likelihood of sputum collection. There were gaps in implementation reach at the stages of contacting and enrolling index participants, enrolling individuals with HIV, and obtaining sputum, especially among those under 18 years and household contact persons.

世界卫生组织（World Health Organization）建议在结核病高负担国家开展结核病（TB）接触者追踪工作。本研究旨在评估南非地区两种结核病接触者追踪策略的实施覆盖效果。Kharitode TB这项整群随机交叉试验，于2016年7月至2020年1月期间，在28家诊所中对比了基于家庭与基于激励的两类接触者追踪方案。每家诊所依次采用两种策略各18个月，两类策略的实施间隔6个月的洗脱期。本研究纳入近期确诊结核病的成人索引病例（index participants）。在基于家庭的组别中，接触者将在居家场景中接受筛查并留取痰液样本；在基于激励的组别中，索引病例向其接触者分发转诊优惠券，接触者前往诊所完成筛查后可获得3.50美元的激励补贴。本研究采用以诊所为随机截距项的混合效应logistic回归（mixed-effects logistic regression）模型，分析与索引病例入组以及接触者留取痰液样本相关的影响因素。在基于家庭的组别中，1269名索引病例中有782人（61.6%）签署了知情同意书，共纳入1882名接触者，其中988人（52.5%）留取了痰液样本；在基于激励的组别中，1295名索引病例中有780人（60.2%）签署了知情同意书，共纳入1940名接触者，其中1431人（73.8%）留取了痰液样本。合并感染人类免疫缺陷病毒（HIV）的索引病例（校正比值比（adjusted odds ratio, aOR）=0.56，95%置信区间（95% CI）：0.38-0.83）或HIV感染状态未知的索引病例（aOR=0.12，95%CI：0.07-0.20）参与本研究的可能性更低。相较于基于家庭的组别，基于激励的组别中的接触者留取痰液样本的可能性更高（aOR=2.12，95%CI：1.80-2.50）。无论隶属于哪个研究组别，存在咳嗽症状（aOR=2.27，95%CI：1.87-2.77）、当前吸烟（aOR=2.22，95%CI：1.63-3.02）以及合并感染HIV（aOR=1.89，95%CI：1.36-3.62）均与接触者留取痰液样本的可能性升高显著相关。本研究在多个实施环节存在覆盖缺口：包括联系并入组索引病例、纳入HIV感染者以及获取痰液样本，该缺口在18岁以下人群以及家庭接触者群体中尤为显著。