上海地区四小学高年级学生结核感染率及影响因素的横断面研究

目的 了解上海地区小学生潜伏结核感染的分布情况并分析影响儿童潜伏结核感染的因素.方法 以上海市浦东新区和杨浦区四所小学四、五年级在校学生作为研究对象,问卷调查形式收集研究对象的基本信息和结核感染相关信息,结核感染T细胞斑点试验(T-SPOT.TB)技术了解结核感染情况,单因素和多因素分析研究影响小学生结核感染状况的因素.结果 本研究共纳入小学生472名,其中有卡介苗接种史者439人,占93.0%,与结核患者既往有过接触的学生10人,占2.1%.472名小学生中16人T-SPOT.TB检测阳性,占3.4%,但无结核相关的临床症状和体征,为潜伏结核感染者.接种卡介苗者潜伏结核感染率为2.7%,未接种者为12.1%(OR:6.972,95% CI:1.834～26.500);有结核接触史者潜伏结核感染率为30.0%,无接触史者为2.8%(OR:16.38,95% CI:3.692～72.700).结论 上海市小学高年级学生的潜伏结核感染率为3.4%,卡介苗接种对预防上海学龄儿童潜伏结核感染有保护作用,而日常生活中与结核患者接触增加了儿童潜伏结核感染的危险性.

Abstract：

Objective To investigate the prevalence of latent tuberculosis infection(LTBI),and to identify the risk factors in primary schoolchildren from Shanghai through the population-based field investigation combined with the tuberculosis infection enzyme-linked immunospot assay(T-SPOT.TB)assay.Methods The children in grade 4 and 5 were enrolled from four primary schools in Pudong new district and Yangpu district of Shanghai.Questionnaire interview was applied to investigate the soeiodemographic and clinical information related to LTBI.The T-SPOT.TB assay was used to detect LTBI in the enrolled subjects.Univaitate and multivariate analyses were used to identify the risk factors associated with LTBI among the primary schoolchildren.Results Totally 472 schoolchildren were enrolled in the present study,with 439(93.0%)being vaccinated with bacillus calmette-guerin (BCG) and ten (2.1%) having contact history with tuberculosis (TB) patients.Among the 472 eligible subjects,16(3.4%) children were T-SPOT.TB positive,who had no clinical symptoms andsigns relevant to TB and were defined as LTBI.The LTBI prevalence in BCG vaccinated and unvaccinated children were 2.7% and 12.1%,respectively (OR:6.972;95%CI:1.834-26.500);those in TB contacts and children without TB contact history were 30.0% and 2.8%, respectively (OR: 16. 38; 95% CI: 3. 692-72. 700). Conclusions The prevalence of LTBI among senior schoolchildren in Shanghai is 3.4%. BCG vaccination is protective for children from LTBI, while daily contacts with TB patients increases the risk of LTBI in schoolchildren.     

Tuberculin reactivity in a pediatric population with high BCG vaccination coverage.

SETTING: The tuberculin skin test (TST) is often included in diagnostic algorithms for tuberculosis (TB) in children. TST interpretation, however, may be complicated by prior Bacillus Calmette-Guerin (BCG) vaccination. We assessed the prevalence of and risk factors for positive TST reactions in children 3 to 60 months of age in Botswana, a country with high TB rates and BCG coverage of over 90%. METHODS: A multi-stage cluster survey was conducted in one rural and three urban districts. Data collected included demographic characteristics, nutritional indices, vaccination status, and prior TB exposure. Mantoux TSTs were administered and induration measured at 48-72 hours. RESULTS: Of 821 children identified, 783 had TSTs placed and read. Of the 759 children with vaccination cards, 755 (99.5%) had received BCG vaccine. Seventy-nine per cent of children had 0 mm induration, 7% had > or =10 mm induration ('positive' TST), and 2% had > or =15 mm. A positive TST was associated with reported contact with any person with active TB (odds ratio [OR] 1.9; 95% confidence interval [CI] 1.02-3.6), or a mother (OR 5.1; 95% CI 2.1-12.4) or aunt (OR 5.3; 95% CI 2.0-14.0) with active TB. TSTs > or =5 mm (but not > or =10 mm) were associated with presence of a BCG scar. Positive reactions were not associated with age, time since BCG vaccination, clinical signs or symptoms of TB, nutritional status, crowding, or recent measles or polio immunization. CONCLUSION: The TST remains useful in identifying children with tuberculous infection in this setting of high TB prevalence and extensive BCG coverage.     

监测封闭社区结核病患者接触者结核感染状况二年的结果分析

目的 监测封闭社区(强制隔离戒毒所)中结核病患者接触者(简称“接触者”)的结核感染状况,并初步分析可能对该社区接触者受结核感染的影响因素。方法 采用结核菌素试验(PPD试验),对封闭社区中2016年10—11月确诊的5例结核病患者的所有接触者(共计792名)每6个月进行1次PPD试验,连续观察2年,其中有25名因各种原因未进行PPD试验,接受PPD试验者767名。依据《WS 288—2017 肺结核诊断》,有卡介苗接种卡痕者硬结平均直径≥10mm、无卡痕者硬结平均直径≥5mm判断为接触者结核感染。分析不同接触程度的767名接触者受MTB感染状况的变化情况。并用logistic回归模型进行社区接触者结核感染的危险因素分析。结果 在调查的封闭社区中,接触者第一次PPD试验结果被判断为结核感染者444例,感染率为57.9%(444/767)。在后续2年的结核感染监测中,323名未感染者中有54例(占16.7%,54/323)接触者变为结核感染;2年中社区接触者受结核感染者共498例,感染率64.9%(498/767)。有54名社区接触者在2年中PPD试验硬结直径减小或消失,由受结核感染变为未感染状态,占10.8%(54/498)。年龄(Wald χ ²=10.942,P=0.001,OR=1.04, 95%CI为1.02~1.06)、接种卡介苗(Wald χ ²=4.533,P=0.033,OR=1.41, 95%CI 为1.03~1.93)、与患者密切接触(Wald χ ²=6.343,P=0.012,OR=1.68, 95%CI 为1.12~2.52),是导致社区接触者结核感染风险增加的相关因素。讨论 封闭社区(强制隔离戒毒所)中结核病患者接触者MTB感染率较高,首次PPD试验筛查未感染者中有近1/6的接触者在2年间转为结核感染;有1/10结核感染者在2年间转为未感染状态。年龄增长、接种卡介苗、与结核病患者密切接触者受结核感染的比例增高。     

Risk factors of treatment default and death among tuberculosis patients in a resource-limited setting

Objective:To evaluate the rates,timing and determinants of default and death among adult tuberculosis patients in Nigeria.Methods:Routine surveillance data were used.A retrospective cohort study of adult tuberculosis patients treated during 2011 and 2012 in two large health facilities in Ebonyi State.Nigeria was conducted.Multivariable logistic regression analyses were used to tdentify independent predictors for treatment default and death.Results:Of 1668 treated patients,the default rate was 157(9.4%),whilst 165(9.9%) died.Also,35.7%(56) of the treatment defaults and 151(91.5%) of deaths occurred during the intensive phase of treatment.Risk of default increased with increasing age(adjusted odds ratio(aOR) 1.2;95%confidence interval(CI)1.1-1.9).smear-negative TB case(aOR 2.3:CI 1.5-3.6).extrapulmonary TB case(aOR 2.7:CI 1.3-5.2).and patients who received the longer treatment regimen(aOR 1,6;1.1-2.2).Risk of death was highest in extrapulmonary TB(aOR 3.0:CI 1.4-6.1) and smear-negative TB cases(aOR 2.4:CI1.7-3.51.rural residents(aOR 1.7:CI 1.2-2.6),HIV co-infected(aOR 2.5:CI 1.7-3.6),not receiving antiretroviral therapy(aOR 1.6:CI 1.1-2.9),and not receiving cotrimoxazole prophylaxis(aOR 1.7:CI 1.2—2.6).Conclusions:Targeted interventions to improve treatment adherence for patients with the highest risk of default or death are urgently needed.This needs to he urgently addressed by the National Tuberculosis Programme.     

Paediatric tuberculosis during universal and selective Bacillus Calmette–Guérin vaccination policy: a nationwide population-based retrospective study,Finland, 1995–2015

IntroductionIn 2006, the Bacillus Calmette–Guérin (BCG) vaccination policy in Finland changed from universal to selective.AimWe assessed the impact of the policy change on tuberculosis (TB) morbidity in children under 5 years and epidemiological trends of paediatric TB in Finland.MethodsWe conducted a nationwide, population-based, retrospective registry study of all newly diagnosed active TB cases younger than 15 years in Finland from 1995 to 2015 by linking data from the National Infectious Diseases Register, Finnish Care Register for Health Care, medical patient records and Finnish Population Information System. We compared the TB incidence rate ratio of under 5 year-olds with universal and selective BCG vaccinations with a Poisson log-linear model and analysed incidence trends among those younger than 15 years with a negative binomial model.ResultsWe identified 139 paediatric TB cases: 50 native (including 24 second-generation migrants) and 89 foreign-born children. The TB rate of under 5 year-olds remained stable after changing to selective BCG vaccination (incidence rate ratio (IRR): 1.3; 95% confidence interval (CI): 0.7–2.3). TB rate in the native population under 15 years increased slightly (IRR = 1.06; 95% CI: 1.01–1.11).DiscussionPaediatric TB cases in Finland were concentrated in families with migrant background from high-TB incidence countries. The native TB morbidity in under 5-year-olds did not increase after the BCG policy revision, suggesting that selective vaccinations can prevent TB in the most vulnerable age group in low-incidence settings. Second-generation migrants under 15 years in Finland with high TB risk are probably increasing.     

Tuberculin reactivity in first‐year schoolchildren in Madagascar

Objective The tuberculin skin test (TST) is an important tool in the diagnosis of tuberculosis infection in children. However, the interpretation of TST may be complicated by prior Bacillus Calmette‐Guerin (BCG) vaccination. We evaluated the effect of vaccination with BCG on TST reactivity in first‐year pupils attending state schools in Antananarivo. Methods STs were performed on 376 first‐year schoolchildren, aged 6 and 7, attending two state primary schools. The relationships between epidemiological information, BCG status (vaccination, BCG scars) and TST reactivity were assessed to compare TST sensitivity between children with and without BCG vaccination and between those with and without a BCG scar. Result The prevalence of positive TST results of ≥5, ≥10 and ≥ 15 mm was 20.2% (76/376), 18.3% (69/376) and 11.4% (43/376), respectively. BCG vaccination was not associated with TST reactivity, whatever the threshold used: ≥5 mm (odds ratio (OR, 1.2; 95% confidence interval (CI), 0.7–2.0); ≥10 mm (OR, 0.9; 95% CI, 0.6–1.7); ≥15 mm (OR, 0.6; 95% CI, 0.3–1.2). Conclusion These results suggest that in Madagascar, a positive TST result indicates TB infection (active or latent) rather than past BCG vaccination. Therefore, high BCG vaccination coverage does not appear to impair the usefulness of the TST as a tool for diagnosing tuberculosis.     

封闭社区结核病患者接触者结核感染状况预测模型

目的 通过监测封闭社区(强制隔离戒毒所)中结核病患者接触者的结核感染状况,分析影响接触者结核感染的可能因素,并构建感染预测模型。方法 采用结核菌素皮肤试验(TST),对封闭社区中2016年10月至2018年11月确诊的13例结核病患者的所有接触者,每6个月进行一次TST,至2019年7月。依据《WS 288—2017 肺结核诊断》相关标准,有卡介苗接种卡痕者硬结平均直径≥10mm、无卡痕者硬结平均直径≥5mm判断为结核病患者接触者(以下简称“接触者”)结核感染。在考虑场所特征(吸毒时间、戒毒次数、首次入本戒毒所)和不考虑场所特征情况下,分别采用Cox回归、条件logistic回归法对年龄、体质量指数(BMI)值、卡介苗接种史、既往结核病史、肺结核可疑症状、接触程度、接触患者分类因素构建感染预测模型,比较各模型对结核感染预测情况及预测值计算的ROC曲线下面积,寻找最优感染预测模型。结果 研究期间共纳入13例结核病患者,以及合格完成TST的检查对象2062名。接触者首次TST阳性而判断为结核感染者1060例,感染率为51.4%(1060/2062)。在后续2年的结核感染监测中,1002名第一次检查未感染者中有267例(26.6%,267/1002)接触者变为感染,其中173例(64.8%,173/267)是在封闭社区中出现新结核病患者后转变为结核感染;2年中社区接触者结核感染者共1327例,感染率64.4%(1327/2062)。使用logistic回归分析,在考虑场所特征情况下,纳入10个因素建立的封闭社区接触者结核感染预测模型为:结核感染=0.041×年龄+0.373×接触程度+0.046×BMI+0.028×吸毒年限-2.285;在不考虑场所特征情况下,纳入7个因素建立的预测模型为:结核感染=0.050×年龄+0.372×接触程度+0.041×BMI-2.282,ROC曲线下面积分别为0.584(95%CI:0.558~0.609)、0.625(95%CI:0.600~0.650),P值均<0.001;对结核感染预测准确率为93.6%(1242/1327)和94.1%(1249/1327)。使用Cox回归分析,在考虑场所特征情况下,建立的结核感染预测模型为:结核感染=0.020×年龄+0.133×接触程度+0.030×BMI+0.013×吸毒年限,ROC曲线下面积为0.633(95%CI:0.608~0.658),P<0.001;不考虑场所特征,建立的预测模型为:结核感染=0.025×年龄+0.135×接触程度+0.028×BMI,ROC曲线下面积为0.625(95%CI:0.600~0.650),P<0.001。结论 不考虑场所特征情况下,封闭社区结核病患者接触者结核感染预测中要考虑的因素包括年龄、BMI值、接触程度,使用两种建模方法的效果接近;如果考虑场所特征,需考虑的因素要增加吸毒年限。在能获得社区接触者随访时间的情况下,使用Cox回归预测效果更好。本研究对封闭社区接触者结核感染预测准确率较高,但尚不完善,亟需探索更多可能的影响因素。     

Annual risk of tuberculosis infection among tribal population of central India

Objective To estimate the annual risk of tuberculosis infection (ARTI) among tribal children of Madhya Pradesh, central India. Methods Community‐based, cross‐sectional tuberculin survey among children aged 1–9 years in the tribal population of Madhya Pradesh. Multistage stratified cluster sampling was used to select a representative random sample of villages predominated by tribal population from selected districts. A total of 4802 children were tuberculin‐tested with 1TU of PPD RT 23 and the reaction sizes read after 72 h. Results A total of 3062 (64%) children had no BCG scar. The frequency distribution of children by reaction sizes indicated a fair mode at 18 mm in the right hand side of the distribution. By mirror‐image technique, the prevalence of infection among children with no recognizable BCG scar was estimated as 6.8% (95% CI: 4.8–8.9%). The ARTI was computed as 1.3% (0.9–1.7%). The corresponding figures for children irrespective of scar status were 7.1% (95% CI: 5.5–8.8%) and 1.3% (1.0–1.7%) respectively. Conclusions The risk of tuberculosis infection in tribal population of Madhya Pradesh, central India is not different from other areas of the country. There is, however, a need to further intensify tuberculosis control measures on a sustained and long‐term basis.     

Factors associated with the development of tuberculosis in BCG immunized children

In this hospital-based case-control study, children attending Siriraj Hospital and Queen Sirikit National Institute of Child Health from 1 December 2002 to 30 June 2003 were studied to define factors associated with TB in BCG immunized children (n = 260). Subjects of the same age and sex were divided into case and control groups by tuberculosis status. Caregivers were interviewed with a structured questionnaire. Data were analyzed by univariate analysis and multivariate analysis for biological factors (birth weight, health status, nutritional status), socioeconomic factors (parental education, education of caregiver, parental occupation, household incomes, and stability of household incomes), and environmental factors (history of contact with a tuberculosis patient, housing ventilation, child's bedroom ventilation, biomass smoke, passive smoking, crowded family and crowded in child's bedroom). Our findings show that children who had contact with TB patients had a very high risk of tuberculosis, even though they were vaccinated at birth. The risks vary according to the closeness level: very close (OR 85.67, 95%CI = 11.33-647.79), close (OR 31.11, 95%CI = 3.93-246.22) and not close (OR 32.70, 95%CI = 4.18-255.94). In order to identify the effect of others variables, the data was reanalyzed only in the group with no history of TB patient contacts (n = 192). Living in a crowded family, which was reflected by an average of 5 or more persons per room, also increased the risk (OR 11.18, 95%CI = 2.35-53.20). The other factor that increased the risk for tuberculosis was passive smoking. Children who were exposed to passive smoking had a 9.31 times increased risk of getting tuberculosis (95%CI = 3.14-27.58). These findings suggest that the public health department must develop a TB surveillance system in high TB prevalence areas, and in high density communities, and encourage smokers in every family to avoid smoking near children. Latent tuberculosis treatment recommendations for TB control cluster, as set by the Bureau of AIDS/TB and STIs, must be implemented in all health centers and an effective TB control program must be reinforced.     

How frequently do tuberculosis screening tests convert in inflammatory bowel disease patients on anti-tumour necrosis factor-alpha? A pilot study

BackgroundTuberculosis reactivation can lead to severe complications in patients treated with anti-tumour necrosis factor-alpha.AimTo assess the usefulness of repeat tuberculosis screening tests in inflammatory bowel disease patients on stable anti-TNF therapy.MethodsCross-sectional study, in patients on prolonged anti-TNF treatment (≥12 months) and basal negative screening for latent tuberculosis. Quantiferon^®-TB Gold In-tube test was performed and then, tuberculin skin test was administered.Results74 patients were included, median duration of anti-TNF treatment was 30 months (IQR 19–54); 47 patients on infliximab and 27 on adalimumab; no patient was on glucocorticoids. Previous BCG vaccination was present in 5 cases. After anti-TNF was started, 4 patients suffered from potential tuberculosis exposure and two cases travelled to endemic areas. The cumulative incidence of tuberculin skin test conversion was 2.7% (95% CI 0.3–9.4%, 2/74), and the incidence rate of tuberculin skin test conversion was 0.83% (95% CI 0.1–2.9%) per patient-year of treatment with anti-TNF drugs. All Quantiferon tests but one (a patient with an indeterminate result and a negative tuberculin skin test) were negative.ConclusionsThe incidence rate of conversion of tuberculosis screening tests among patients on anti-TNF treatment seems to be low and these conversions were diagnosed based on a positive tuberculin skin test and were discordant with Quantiferon testing.     

结核病疫苗的抗结核免疫机制的研究进展

结核病是由结核分枝杆菌(Mycobacterium Tuberculosis,MTB)所引起的一种慢性传染病,严重危害人类健康,是目前全球范围内,尤以发展中国家为首,是受危害最为严重的慢性传染病之一。目前,预防结核病最常见且有效的疫苗是卡介苗(Bacillus Calmette-Guérin,BCG),但由于其对成人肺部结核保护作用的不确定性,再加上外界因素的改变也使卡介苗难以满足人类预防结核病的迫切需求,因此,新型抗结核疫苗的研发显得格外紧迫和重要。本文将介绍减毒活疫苗VPM1002疫苗,蛋白质/佐剂疫苗H4/H56:IC31疫苗,病毒载体疫苗腺病毒载体疫苗和其他已经进入临床试验的疫苗,以及一些尚在研究的抗结核免疫机制的研究现状,为以后的结核病防治提供参考。     

Risk factors for death during treatment in pulmonary tuberculosis patients in South India: A cohort study

ObjectiveIdentifying the risk factors for deaths during tuberculosis (TB) treatment is important for achieving the vision of India's National Strategic Plan of ‘Zero Deaths’ by 2025. We aimed to determine the proportion of deaths during TB treatment and its risk factors among smear positive pulmonary TB patients aged more than 15 years.Study designWe performed a cohort study using data collected for RePORT India Consortium (Regional Prospective Observational Research in Tuberculosis).SettingRevised TB Control Program (RNTCP) in three districts of South India.ParticipantsThe cohort consisted of newly diagnosed drug sensitive patients enrolled under the Revised National TB Control Program during 2014–2018 in three districts of southern India. Information on death was collected at homes by trained project staff.Primary outcome measuresWe calculated ‘all-cause mortality’ during TB treatment and expressed this as a proportion with 95% confidence interval (CI). Risk factors for death were assessed by calculating unadjusted and adjusted relative risks with 95% CI.ResultsThe mean (SD) age was of the 1167 participants was 45 (14.5) years and 79% of them were males. Five participants (0.4%) were HIV infected. Among the males, 560 (61%) were tobacco users and 688 (75%) reported consuming alcohol. There were 47 deaths (4%; 95% CI 3.0–5.3) of which 28 deaths (60%) occurred during first two months of treatment. In a bi-variable analysis, age of more than 60 years (RR 2.27; 95%CI: 1.24–4.15), male gender (RR 3.98; 95% CI: 1.25–12.70), alcohol use in last 12 months (RR 2.03; 95%CI: 1.07–3.87), tobacco use (RR 1.87; 95%CI: 1.05–3.36) and severe anaemia (RR 3.53: 95%CI: 1.34–9.30) were associated with a higher risk of death. In adjusted analysis, participants with severe anaemia (<7gm/dl) had 2.4 times higher risk of death compared to their counterparts.ConclusionThough deaths during TB treatment was not very high, early recognition of risk groups and targeted interventions are required to achieve zero TB deaths.     

The current situation and treatment of childhood tuberculosis]

We performed a retrospective analysis of 394 patients who were treated for active tuberculosis (TB) at our hospital from 1976 to 1997. The diagnosis criteria for establishing TB were history of direct contact with TB patients, tuberculin skin test reactivity, positive bacteriology and radiographic findings compatible with TB. There were 192 males and 202 females (age range 1 month to 18 years of age, mean 6.3 years of age). Fifty-four percent of the cases were under 5 years of age. Primary pulmonary TB was presented in 200, post primary pulmonary TB in 97, pleural effusion in 53, endbronchial TB in 4, TB meningitis (TBM) in 28, miliary TB in 28 and other extra-pulmonary TB in 31. A history of contact with the patients was obtained in 72.8% of cases. Two hundred and thirty (58.4%) had received BCG, 134 (34%) no BCG, 30 (7.6%) were unclear. Especially, under 5 years of age, only 29 (13.6%) had received BCG. TBM is not disappeared in Japan and there were 28 cases with TBM. Fifteen patients out of them recovered completely, 8 patients recovered with severe neurological sequelae which included mental retardation, motor weakness, seizures and hydrocephalus and 5 patients died. Twenty-six had no BCG. Particularly in 1990s, we had experienced 4 dead TBM cases, 1 multi-drug resistant (MDR) TBM case and 1 TBM case due to nosocomial infection. Children with TBM should received 12-month regimen using initial daily treatment with isoniazid, rifampin, pyrazinamide, and streptmycin, followed by isoniazid and rifampin administered daily. Pulmonary TB in children is successfully treated with 6-month standard chemotherapy using isoniazid, rifampin, and pyrazinamide daily for 2 months, followed by isoniazid and rifampin daily for 4 months. In order to promote TB control and eliminate childhood TB, especially in infants, the following is necessary; 1) early detection and treatment of adult TB patients, source of infection, 2) prompt and appropriate contact examination and chemoprophylaxis, 3) BCG vaccination during early infancy, 4) protection from MDR TB are most important in Japan.     

Use of an interferon-gamma release assay to diagnose latent tuberculosis infection in foreign-born patients

BACKGROUND: The tuberculin skin test (TST) has a low specificity in the setting of bacille Calmette-Guérin (BCG) vaccination. Interferon-gamma release assays (IGRAs) appear to be more specific but have not been validated in this population under routine clinical conditions. We sought to validate the routine clinical use of the T-SPOT.TB test (Oxford Immunotec; Oxford, UK), an IGRA, in a predominantly foreign-born population with a high rate of BCG vaccination. METHODS: We compared the TST and the T-SPOT.TB test in 96 subjects at a New York City Department of Health tuberculosis clinic. We aimed to determine which test better predicted being a close contact of a case of active tuberculosis, a surrogate for latent tuberculosis infection. RESULTS: A positive T-SPOT.TB test result was strongly associated with being a close contact of a case of active tuberculosis after adjustment for potential confounders (adjusted odds ratio, 2.9; 95% confidence interval, 1.1 to 7.3; p = 0.03). A positive TST result was associated with being a contact only in subjects without BCG vaccination (p = 0.02). The T-SPOT.TB test was more specific for being a close contact than the TST (p < 0.001). Specificity in BCG-vaccinated subjects was 3% for the TST compared with 70% for the T-SPOT.TB test (p < 0.001). CONCLUSIONS: The T-SPOT.TB test is superior in routine clinical use to the TST for identifying high-risk individuals among foreign-born populations with high rates of BCG vaccination.     

Contact examination for tuberculosis in Hong Kong is useful.

SETTING: The tuberculosis programme of the Hong Kong Government Tuberculosis and Chest Service. OBJECTIVE: To determine the outcome of examination of household contacts in Hong Kong. DESIGN: A retrospective cohort study of all household contacts of 970 randomly selected index cases from a total of 5757 registered for treatment with the Chest Service. RESULTS: Of 2678 household contacts (three/index case) identified, 90% were examined; 41 active cases were found, at a rate of 1720/100000 (95%CI 1238-2329). The rate was highest among two extremes of age, 3604/100000 (95%CI 990-3615) in children < or = 5 years and 3347/100000 (95%CI 1456-6489) in those >60 years of age. Contacts of index cases whose sputum smear and culture were positive had the highest rate of disease, 2904/100000 (95%CI 1669-4673); but contacts with negative bacteriology also had a high rate of 1478/100000 (95%CI 678-2789). Active cases identified through contact tracing could be source cases rather than secondary cases. Eight per cent of children aged < or = 5 years had positive tuberculin reactions; as BCG vaccination is given to all newborns, with 99% coverage in Hong Kong in the past 30 years, it was difficult to estimate the rate of infection in these children. CONCLUSION: In Hong Kong, an area with an intermediate burden of tuberculosis, contact investigation is a very useful procedure for active case finding.     

Latent tuberculosis infection among undergraduate medical students in Rio de Janeiro State, Brazil.

SETTING: Five medical schools in three cities with different tuberculosis (TB) incidence rates in Rio de Janeiro State, Brazil. OBJECTIVE: To estimate prevalence of and associated factors for latent tuberculosis infection (LTBI) among medical students. DESIGN: A cross-sectional survey was conducted among undergraduate students in pre-clinical, early and late clinical years from schools in cities with low (28/100,000), intermediate (63/100,000) and high (114/100,000) TB incidence rates. Information on socio-demographic profile, previous BCG vaccination, potential TB exposure, co-morbidity and use of respiratory protective masks was obtained. A tuberculin skin test (TST) was performed using the Mantoux technique by an experienced professional. A positive TST, defined as induration > or = 10 mm, was considered LTBI. RESULTS: LTBI prevalence was 6.9% (95%CI 5.4-8.6). In multivariate analysis, male sex (adjusted odds ratio [aOR] 1.8; 95% CI 1.1-3.0), late clinical years (aOR 1.9; 95% CI 1.01-3.5), intermediate TB incidence (aOR 4.3; 95% CI 1.3-14.6) and high TB incidence in the city of medical school (aOR 5.1; 95% CI 1.6-16.8) were significantly associated with LTBI. CONCLUSIONS: The higher prevalence of LTBI in late clinical years suggests that medical students are at increased risk for nosocomial Mycobacterium tuberculosis infection. The implementation of a TB control program may be necessary in medical schools, particularly in cities with higher TB incidence.     

Identifying Predictors of Interferon-γ Release Assay Results in Pediatric Latent Tuberculosis: A Protective Role of Bacillus Calmette-Guerin?: A pTB-NET Collaborative Study

Rationale: Interferon-γ (IFN-γ) release assays are widely used to diagnose latent infection with Mycobacterium tuberculosis in adults, but their performance in children remains incompletely evaluated to date. Objectives: To investigate factors influencing results of IFN-γ release assays in children using a large European data set. Methods: The Pediatric Tuberculosis Network European Trials group pooled and analyzed data from five sites across Europe comprising 1,128 children who were all investigated for latent tuberculosis infection by tuberculin skin test and at least one IFN-γ release assay. Multivariate analyses examined age, bacillus Calmette-Guérin (BCG) vaccination status, and sex as predictor variables of results. Subgroup analyses included children who were household contacts. Measurements and Main Results: A total of 1,093 children had a QuantiFERON-TB Gold In-Tube assay and 382 had a T-SPOT.TB IFN-γ release assay. Age was positively correlated with a positive blood result (QuantiFERON-TB Gold In-Tube: odds ratio [OR], 1.08 per year increasing age [P < 0.0001]; T-SPOT.TB: OR, 1.14 per year increasing age [P < 0.001]). A positive QuantiFERON-TB Gold In-Tube result was shown by 5.5% of children with a tuberculin skin test result less than 5 mm, by 14.8% if less than 10 mm, and by 20.2% if less than 15 mm. Prior BCG vaccination was associated with a negative IFN-γ release assay result (QuantiFERON-TB Gold In-Tube: OR, 0.41 [P < 0.001]; T-SPOT.TB: OR, 0.41 [P < 0.001]). Young age was a predictor of indeterminate IFN-γ release assay results, but indeterminate rates were low (3.6% in children < 5 yr, 1% in children > 5 yr). Conclusions: Our data show that BCG vaccination may be effective in protecting children against Mycobacterium tuberculosis infection. To restrict use of IFN-γ release assays to children with positive skin tests risks underestimating latent infection.     

Risk factors of tuberculosis in Mizoram: First report of the possible role of water source

BackgroundVarious risk factors of tuberculosis have been studied across the globe, but these may be altered over time and can be specific to geographical regions and there is not much information available from Northeastern region of India. This study aims to investigate the various risk factors of tuberculosis and analyze the presence of any less-established risk factors.MethodsA total of 400 TB cases and 840 healthy controls were interviewed from December 2017 - June 2020. Logistic regression model was used to analyze associated risk factors. Patients were categorized into pulmonary and extrapulmonary TB.ResultsClinical presentation such as fever, cough, weight loss, chest pain and night sweats were more prominent among pulmonary TB patients. The most common mode of diagnosis among pulmonary and extrapulmonary TB were GeneXpert and X-ray, respectively. Tuberculosis was found to be strongly prevalent among patients from lower socio-economic status, less educated, unemployed and improper housing condition. Other risk factors associated were alcohol consumption, neighbours with TB, travel history, no BCG vaccine, mass gathering, and non-ideal weight. An interesting less-established risk factor that demands attention is the source of water supply (p-0.017, OR-2.313, CI: 1.160–4.613), which was significant in this study.ConclusionOur data suggests that apart from all the well-established risk factors for TB, water supply might play a crucial role towards the transmission of TB, since proper hospital waste water treatment is yet to be adopted in Mizoram, Northeast India. From a public health standpoint, this highlights the need for further research in this area.     

A case-control study of protection against tuberculosis by BCG revaccination in Recife, Brazil.

SETTING: Metropolitan region of Recife, Brazil. OBJECTIVE: To estimate the additional protection against tuberculosis (TB) provided by a second dose of bacille Calmette-Guérin (BCG) vaccine. DESIGN: Case-control study. Cases were cases of TB newly diagnosed by the TB control programme, independent of clinical form. Three matched neighbourhood controls were selected using a systematic routine, starting from the case's address. The matching was within the age groups 7-9, 10-14 and 15-19 years. RESULTS: Analysis was conducted among 169 cases and 477 controls. For the efficacy of BCG revaccination against TB overall, matched (crude) vaccine effectiveness (VE) was -3 (95% CI -50-29) and matched (adjusted) VE was 8 (95% CI -77-52). CONCLUSIONS: This study suggests that a second dose of BCG does not offer additional protection. Revaccination should not be offered. As large numbers of subjects are already vaccinated and vaccine appears to offer some protection in older subjects, further studies with larger sample sizes could investigate the potential efficacy of revaccination with BCG in the age group > or = 15 years.     

预防与治疗性结核病疫苗的研究进展

迄今为止,结核病(Tuberculosis,TB)唯一被批准用于预防TB的疫苗是100多年前由牛分枝杆菌减毒而成的卡介苗(BCG)。BCG可预防小儿TB,但还无法预防成人感染TB。此外耐多药TB(MDR-TB)患者不断增多,这使全球TB感染的发病率及死亡率下降仍达不到世界卫生组织(WHO)的目标。因此,需要一种新的有效的TB疫苗和基础-增强免疫策略来替代BCG预防TB的感染。在这篇综述中,我们分析了目前已研发的预防和治疗性疫苗以及疫苗佐剂的研究进展,目的是使我们对TB的感染和防控的现状有全面的了解。