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Table 1 Studies investigating effective screening strategies for paediatric LTBI in high-risk populations within low-burden countries (by study population)

From: Recommendations for the screening of paediatric latent tuberculosis infection in indigenous communities: a systematic review of screening strategies among high-risk groups in low-incidence countries

First Author
(Reference)
Year Study setting Study population Sample size Study objective Screening program/strategy Screening tool used Findings/Recommendations regarding screening strategy
Indigenous Communities
 Alvarez [24] 2014 Nunavut, Canada A high-risk Indigenous community in Iqaluit, Nunavut 444 To evaluate a door-to-door LTBI screening strategy in a Canadian Indigenous community Door-to-door screening, with targeting of dwellings screened based on location within a high-incidence area (> 5 cases in the last 5 years) TST • Screening based on high-risk location (rather than individual factors) was effective in this setting
• 42 previously unidentified cases were identified (34% of the total incidence in the area at the time).
• These cases would not have been identified via the current conventional screening practices
Pre-kindergarten or school-aged children
 Flaherman [31] 2007 California, USA Pre-kindergarten children in California NAa To evaluate the cost-effectiveness of universal vs. targeted screening for paediatric LTBI Compared universal screening for paediatric LTBI prior to kindergarten entry to targeted screening based on the presence of at least one risk factor for LTBI TST • Universal screening had a higher incremental cost compared to targeted screening per prevented case.
• Targeted screening would result in 1.89 missed TB cases per year (in areas with at least 252,405 children aged 5 among which TST testing is conducted)
 Gounder [32] 2003 New York, USA School-age children in New York receiving a TST between 1991 and 1998 788,283 To assess adherence and utility of a change in paediatric LTBI screening policy Universal screening of new entrants to primary and secondary school replaced by screening only in secondary school entrants TST • More targeted screening among high-risk secondary school children would be more cost-effective (higher likelihood of identifying LTBI cases)
 Yuan [28] 1995 Toronto, Canada High-risk elementary and secondary school students in Toronto, Canada 720 To evaluate a school-based screening program in Toronto, Canada Targeted screening based on risk, Indigenous children and children born in a country of high TB endemicity were selectively screened via TST (> 10 mm considered positive) TST • Poor participation (40.6%) resulted in the fact that the program prevented only 3 potential TB cases, therefore not cost-effective (cost to prevent > cost to treat, although this should be considered with caution, given that indirect costs of TB (such as QALYs), and the costs of treating secondary cases were not included in the cost-effectiveness analysis).
• However, may be more cost-efficient in higher-incidence communities
 Taylor [37] 2008 Newcastle, UK Children who had a QFT-G performed at Newcastle general hospital 120 To evaluate the effect of the NICE guidelines on paediatric TB screening practices NICE guidelines mandate the follow-up of TST+ patients with a QFT-G or T-SPOT to determine further action. Due to the lack of data on the sensitivity of IFNy assays in children, this may identify fewer cases than with the use of the TST alone for decision-making regarding possible LTBI cases TST and QFT-GIT • 85% fewer would have received prophylaxis under the NICE guidelines (compared to prior to implementation of the guidelines)
• 2% of possible active TB cases would not have been identified.
• TB management based on IGRAs is more economical in low-burden settings, although it may also be associated with lower case identification
 Minodier [30] 2010 Montreal, Canada Immigrant school children and their classmates in Montreal, Canada 4375 (3401 tests read) To evaluate a school-based LTBI screening and treatment program for immigrant children in Canada Children (10–12 years old) in classes with a high proportion of immigrants were targeted for screening by TST TST • Program cost-effectiveness and case identification could have been improved by targeting at-risk children, rather than at-risk classroom groups
• Overall 777 (22.8%) TST+ (≥10 mm)
• More specific case selection/targeting would be beneficial in low-burden settings
• Advocates the use of a risk factor questionnaire for more targeted screening.
Immigrants (including internationally adopted children)
 Panchal [33] 2014 Leicester, UK Recent immigrants to Leicester, UK 59,007 (10,515 children < 16 yrs) To evaluate the effectiveness of LTBI screening after first primary care registration of recent immigrants (11-year retrospective study) Targeted screening of immigrants recently registered with primary care services Not mentioned • 31.2% (15/48) of TB cases could have been prevented through screening in < 16 yrs. b at the time of first primary care registration after immigration.
• Using first primary care registration as a flag for targeted screening of immigrants is effective in a high-burden community within a low-burden country.
 Pareek [35] 2011 UK 177 Primary care facilities in the UK 177 (primary care centres) To evaluate the different screening methods used to screen immigrants for LTBI in primary care facilities throughout the UK Screening of recent immigrants registering at primary care centres (methods of screening varied across centres) TST and IGRA • Only 107/177 (60.4%) of primary care facilities screened for LTBI.
• Primary care centres in high-risk areas were less likely to screen immigrants (35.0% vs. 68.1%, p < 0.0001)
• More targeted and evidence-based screening policies needed.
• Of those that did screen for LTBI, factors for targeting screening included: < 16 yrs. from countries with a TB incidence > 40/100,000, anyone from countries with a TB incidence > 500/100,000, or immigrants from Sub-Saharan Africa
 Pareek [34] 2011b Lancashire, Yorkshire and London, UK Immigrants attending healthcare centres in the UK 1229 (< 16 yrs., n = 36) To evaluate the cost-effectiveness of targeting LTBI screening in immigrants based on age group and TB incidence in country of origin Various screening methods for immigrants evaluated based on incidence in country of origin QFT-GIT Most cost-effective screening strategy: screening those < 16 yrs. from any country with TB incidence > 40/100,000 (and > 250/100,000 for 16–35 yrs)
 Trehan [36] 2008 USA Internationally adopted children in the US (who had a TST within 2 months of arrival) 527 (191 repeat-tested) To investigate whether repeat testing of internationally adopted children increases LTBI case identification Repeat testing (via TST) of internationally adopted children 3 months or more after arrival (with the initial test having been taken within 2 months of arrival) TST • 31/191 (17.7%) of those with an initially negative TST had a positive follow-up TST.
• Having a positive follow-up TST was associated with malnourishment
• Repeat TST testing in vulnerable groups may be warranted to identify further cases
  1. aNot applicable, cost-effectiveness and clinical decision analysis b yrs. = years old QFT-GIT = Quantiferon Gold In-Tube