Yield of tuberculosis contact investigation in a low-incidence country

Borraccino, Alberto; Migliore, Enrica; Piccioni, Pavilio; Baussano, Iacopo; Carosso, Aurelia; Bugiani, Massimiliano

doi:10.1016/j.jinf.2013.12.005

Cited by 9 publications

(9 citation statements)

References 18 publications

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“…The yield per contact of active TB among contacts of pulmonary index cases presented here (2.6%) is high relative to other studies in high-income settings. A systematic review of contact tracing outcomes found a grouped yield per contact of TB in high-income countries of 1.4%, 8 a similar study to ours in Italy found a yield per contact of active disease of 0.71%, 17 and a study in Amsterdam found 0.79% of contacts had prevalent TB and 0.39% incident TB, 18 although these comparisons do not account for differences in smear-positivity prevalence. There are no comparable estimates of the yield per contact of LTBI among child contacts.…”

Section: Discussionmentioning

confidence: 58%

“… 11 It is also comparable to recent findings from the USA where the corresponding figures were 94% and 86% for smear-positive and smear-negative, culture-positive index cases, respectively, 24 and higher than the figure in Piedmont, Italy (77%). 17 Similarly, the proportion of identified contacts who were evaluated (88%) was higher than the north central London (74% precohort review, 82% postcohort review) and US figures (82% for smear-positives, 81% for smear-negatives). These figures suggest London TB clinics undertake high quality contact tracing, although further improvements in certain groups may be feasible.…”

Section: Discussionmentioning

confidence: 91%

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An evaluation of tuberculosis contact investigations against national standards

Cavany

Sumner

Vynnycky

et al. 2017

Thorax

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BackgroundContact tracing is a key element in England's 2015 collaborative TB strategy, although proposed indicators of successful contact tracing remain undescribed.MethodsWe conducted descriptive and multivariable analyses of contact tracing of TB cases in London between 1 July 2012 and 31 December 2015 using cohort review data from London's TB Register, identifying characteristics associated with improved indicators and yield.ResultsOf the pulmonary TB cases notified, 60% (2716/4561) had sufficient information for inclusion. Of these, 91% (2481/2716) had at least 1 contact (median: 4/case (IQR: 2–6)) identified, with 86% (10 251/11 981) of these contacts evaluated. 4.1% (177/4328), 1.3% (45/3421) and 0.70% (51/7264) of evaluated contacts of pulmonary smear-positive, pulmonary smear-negative and non-pulmonary cases, respectively, had active disease. Cases who were former prisoners or male were less likely to have at least one contact identified than those never imprisoned or female, respectively. Cases diagnosed at clinics with more directly observed therapy or social workers were more likely to have one or more contacts identified. Contacts screened at a different clinic to their index case or of male index cases were less likely to be evaluated than those screened at the same clinic or of women, respectively; yield of active disease was similar by sex. 10% (490/4850) of evaluated child contacts had latent TB infection.ConclusionsThese are the first London-wide estimates of TB contact tracing indicators which are important for monitoring the strategy's success and informing risk assessment of index cases. Understanding why differences in indicators occur between groups could improve contact tracing outcomes.

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Section: Discussionmentioning

confidence: 58%

Section: Discussionmentioning

confidence: 91%

An evaluation of tuberculosis contact investigations against national standards

Cavany

Sumner

Vynnycky

et al. 2017

Thorax

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“…It has been well documented that household exposure to a known TB case is the primary risk factor for TB [12], especially for children [13]. Adolescents, therefore, may acquire TB infection at school [14] or from the household [15,16]. Clearly in China there is a lack of studies comparing the roles of households and of the classroom in adolescent TB transmission.…”

Section: Introductionmentioning

confidence: 99%

Tuberculosis Transmission in Households and Classrooms of Adolescent Cases Compared to the Community in China

Pan

Lin

Lan

et al. 2018

IJERPH

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The aim of this paper is to evaluate the link between the history of exposure to tuberculosis (TB) in the household and diagnosed TB cases at school, and to compare the detection rate of active TB among household contacts and classroom contacts of adolescent TB cases with the rates among contacts of healthy controls. From November 2016 to December 2017, a prospective matched case-control study was conducted using passively identified index adolescent student cases from the TB surveillance system and healthy controls (matched by county, school type, sex, age and ethnicity). Contacts in households and classrooms of index cases and of controls were investigated. Matched tabulation of 117 case-control pairs revealed exposure to TB in the household as a strong risk factor (odds ratio (OR) = 21.0, 95% confidence interval (CI): 3.4, 868.6). Forty-five (case detection rate 0.69%) and two (case detection rate 0.03%) new active TB cases were detected among 6512 and 6480 classroom contacts of the index cases and controls, respectively. Having an index case in the classroom significantly increased the risk of classmates contracting active TB (OR = 22.5, 95% CI: 5.9, 191.4). Our findings suggested that previous exposure to TB in the household could lead a child to catch TB at school, then spread TB to classmates.

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“…Similar to Sweden, the risk was also higher among children born in a TB endemic country [ 16 ]. Close-contact investigations among immigrant population have been shown to be cost-effective, although foreign-born contacts are more likely to remain unidentified [ 21 , 22 ]. It is likely that investigations among the immigrant community identify also old infections resulting from TB exposure abroad.…”

Section: Discussionmentioning

confidence: 99%

Tuberculosis contact investigation results among paediatric contacts in low-incidence settings in Finland

et al. 2021

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Tuberculosis (TB) risk is highest immediately after primary infection, and young children are vulnerable to rapid and severe TB disease. Contact tracing should identify infected children rapidly and simultaneously target resources effectively. We conducted a retrospective review of the paediatric TB contact tracing results in the Hospital District of Helsinki and Uusimaa from 2012 to 2016 and identified risk factors for TB disease or infection. Altogether, 121 index cases had 526 paediatric contacts of whom 34 were diagnosed with TB disease or infection. The maximum delay until first contact investigation visit among the household contacts under 5 years of age with either TB disease or infection was 7 days. The yield for TB disease or infection was 4.6% and 12.8% for household contacts, 0.5% and 0% for contacts exposed in a congregate setting and 1.4% and 5.0% for other contacts, respectively. Contacts born in a TB endemic country (aOR 3.07, 95% CI 1.10–8.57), with household exposure (aOR 2.96, 95% CI 1.33–6.58) or a sputum smear positive index case (aOR 3.96, 95% CI 1.20–13.03) were more likely to have TB disease or infection.Conclusions: Prompt TB investigations and early diagnosis can be achieved with a well-organised contact tracing structure. The risk for TB infection or disease was higher among contacts with household exposure, a sputum smear positive index case or born in a TB endemic country. Large-scale investigations among children exposed in congregate settings can result in a very low yield and should be cautiously targeted. What is Known:• Vulnerable young children are a high priority in contact tracing and should be evaluated as soon as possible after TB exposure What is New:• Prompt investigations for paediatric TB contacts and early diagnosis of infected children can be achieved with a well-organised contact tracing structure• Large-scale investigations among children exposed in congregate settings can result in a very low yield and should be cautiously targeted

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Yield of tuberculosis contact investigation in a low-incidence country

Cited by 9 publications

References 18 publications

An evaluation of tuberculosis contact investigations against national standards

An evaluation of tuberculosis contact investigations against national standards

Tuberculosis Transmission in Households and Classrooms of Adolescent Cases Compared to the Community in China

Tuberculosis contact investigation results among paediatric contacts in low-incidence settings in Finland

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