Background In January 2016, clinical TB guidance in the UK changed to no longer recommend screening contacts of non-pulmonary, non-laryngeal (ETB) index cases. However, no new evidence was cited for this change, and there is evidence that screening these contacts may be worthwhile. The objective of this study was to estimate the cost-effectiveness of screening contacts of adult ETB cases and adult pulmonary or laryngeal TB (PTB) cases in London, UK.
Methods We carried out a cross-sectional analysis of data collected on TB index cases and contacts in the London TB register and an economic evaluation using a static model describing contact tracing outcomes. Incremental cost-effectiveness ratios (ICERs) were calculated using no screening as the baseline comparator. All adult TB cases (≥15 years old) in London from 2012 to 2015, and their contacts, were eligible (2465/5084 PTB and 2559/6090 ETB index cases were included).
Results Assuming each contact with PTB infects one person/month, the ICER of screening contacts of ETB cases was £78 000/quality-adjusted life-years (QALY) (95% CI 39 000 to 140 000), and screening contacts of PTB cases was £30 000/QALY (95% CI 18 000 to 50 000). The ICER of screening contacts of ETB cases was £30 000/QALY if each contact with PTB infects 3.4 people/month. Limitations of this study include the use of self-reported symptomatic periods and lack of knowledge about onward transmission from PTB contacts.
Conclusions Screening contacts of ETB cases in London was almost certainly not cost-effective at any conventional willingness-to-pay threshold in England, supporting recent changes to National Institute for Health and Care Excellence national guidelines.
- health economist
- bacterial infection
- respiratory infection
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Contributors SMC, EV and TS conceived and designed the work, with input from all other authors. CSA and HM are responsible for the acquisition and maintenance of the data. SMC undertook the analysis with advice from all other authors. FS calculated the costs. All authors contributed to the interpretation of the data. SMC wrote the first draft of the paper and all authors contributed to subsequent drafts. All authors approve the work for publication and agree to be accountable for the work.
Funding SMC and FS are funded separately by a joint PHE-LSHTM studentship in Infectious Disease Modelling. RGW is funded by the UK Medical Research Council (MRC) and the UK Department for International Development (DFID) (under the MRC/DFID Concordat agreement that is also part of the EDCTP2 programme supported by the European Union (MR/J005088/1)), the Bill and Melinda Gates Foundation (TB Modelling and Analysis Consortium: OPP1084276 and SA Modelling for Policy: #OPP1110334) and UNITAID (4214-LSHTM-Sept15; PO #8477-0-600). CSA, EV, HM and HLT are employed by PHE, a government agency, and received no other source of funding. TS is funded by the Bill and Melinda Gates Foundation (SA Modelling for Policy: #OPP1110334). SMC made the final decision to submit and had access to all data.
Competing interests None declared.
Patient consent Not required.
Ethics approval Ethical approval was not required. The data analysed were routinely collected surveillance data held by PHE under Section 251 of the NHS Act 2006. All records were anonymised before analysis.
Provenance and peer review Not commissioned; externally peer reviewed.
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