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