Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, England, United Kingdom.
Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi.
PLoS One. 2020 Mar 17;15(3):e0230376. doi: 10.1371/journal.pone.0230376. eCollection 2020.
Household contacts of patients with active pulmonary tuberculosis (TB) often have latent TB infection, and are at risk of progression to disease. We set out to investigate whether index TB case HIV status was linked to a higher probability of latent TB infection among household contacts.
Data were collected prospectively from participants in the intervention arm of a household cluster-randomised trial in two South Africa provinces (Mangaung, Free State, and Capricorn, Limpopo). In intervention group households, TB contacts underwent HIV testing and tuberculin skin testing (TST). TST induration was estimated at two cut-offs (≥5mm, ≥10mm). Multilevel Bayesian regression models estimated posterior distributions of the percentage of household contacts with TST induration ≥5mm and ≥10mm by age group, and compared the odds of latent TB infection by key risk factors including HIV status index case age and study province.
A total of 2,985 household contacts of 924 index cases were assessed, with most 2,725 (91.3%) undergoing TST. HIV prevalence in household contacts was 14% and 10% in Mangaung and Capricorn respectively. Overall, 16.8% (458/2,725) had TST induration of ≥5mm and 13.1% (359/2,725) ≥10mm. In Mangaung, children aged 0-4 years had a high TST positivity prevalence compared to their peers in Capricorn (22.0% vs. 7.6%, and 20.5% vs. 2.3%, using TST thresholds of ≥5mm and ≥10mm respectively). Compared to contacts from Capricorn, household contacts living in Mangaung were more likely to have TST induration ≥5mm (odds ratio [OR]: 3.08, 95% credibility interval [CI]: 2.13-4.58) and ≥10mm (OR: 4.52, 95% CI: 3.03-6.97). There was a 90% and 92% posterior probability that the odds of TST induration ≥5mm (OR: 0.79, 95% CI: 0.56-1.14) and ≥10mm (OR: 0.77, 95% CI: 0.53-1.10) respectively were lower in household contacts of HIV-positive compared to HIV-negative index cases.
High TST induration positivity, especially among young children and people living in Mangaung indicates considerable TB transmission despite high antiretroviral therapy coverage. Household contact of HIV-positive index TB cases were less likely to have evidence of latent TB infection than contacts of HIV-negative index cases.
活动性肺结核（TB）患者的家庭接触者通常患有潜伏性 TB 感染，并且有发展为疾病的风险。我们旨在研究索引 TB 病例的 HIV 状况是否与家庭接触者中潜伏性 TB 感染的可能性增加有关。
数据是从南非两个省份（自由州的曼加翁和林波波的卡普里科恩）的家庭群组随机试验干预组的参与者中前瞻性收集的。在干预组家庭中，TB 接触者接受了 HIV 检测和结核菌素皮肤试验（TST）。TST 硬结在两个截止值（≥5mm，≥10mm）处进行评估。多级贝叶斯回归模型估计了按年龄组的 TST 硬结≥5mm 和≥10mm 的家庭接触者的百分比的后验分布，并比较了关键风险因素（包括 HIV 状态索引病例年龄和研究省份）的潜伏性 TB 感染的可能性。
共评估了 924 例索引病例的 2985 名家庭接触者，其中大多数（2725 人）进行了 TST。家庭接触者中的 HIV 患病率分别为 14%和 10%，在曼加翁和卡普里科恩。总体而言，16.8%（458/2725）的 TST 硬结≥5mm，13.1%（359/2725）的 TST 硬结≥10mm。在曼加翁，0-4 岁的儿童与卡普里科恩的同龄人相比，TST 阳性率较高（使用 TST 阈值≥5mm 和≥10mm 分别为 22.0%比 7.6%，20.5%比 2.3%）。与来自卡普里科恩的接触者相比，居住在曼加翁的家庭接触者更有可能出现 TST 硬结≥5mm（比值比[OR]：3.08，95%置信区间[CI]：2.13-4.58）和≥10mm（OR：4.52，95%CI：3.03-6.97）。家庭接触者的 TST 硬结≥5mm（OR：0.79，95%CI：0.56-1.14）和≥10mm（OR：0.77，95%CI：0.53-1.10）的可能性较低的后验概率分别为 90%和 92%，这表明 HIV 阳性指数病例的 TST 硬结阳性率较高，尤其是在年幼儿童和曼加翁地区，尽管抗逆转录病毒治疗覆盖率较高，但仍存在大量的 TB 传播。与 HIV 阴性指数病例的接触者相比，HIV 阳性指数 TB 病例的家庭接触者更不可能有潜伏性 TB 感染的证据。
