Time to rethink approaches to migrant health screening
Authors: Sally Hargreaves, Laura Nellums, Jon S Friedland
Journal: The Lancet (2016)

The elimination of tuberculosis in Europe is a key public health priority,1Lonnruth K Migliori GB Abubakar I et al.Towards tuberculosis elimination: an action framework for low-incidence countries.Eur Respir J. 2015; 45: 928-952PubMed Google Scholar yet unprecedented levels of migration, especially from low-income or middle-income countries, pose challenges to achieving this goal. The overall incidence of tuberculosis in migrants is increasing in several countries, and—for example—migrants comprise more than 70% of all newly diagnosed cases in the UK, Sweden, the Netherlands, and Norway.2European Centre for Disease Prevention and ControlAssessing the burden of key infectious diseases in migrant populations in the EU/EEA. European Centre for Disease Prevention and Control, Stockholm2014Google Scholar Migrants are at higher risk of clinical tuberculosis as a result of coming from countries with a high burden of infection, the poverty they might face on arrival, and a plethora of barriers to accessing free statutory health care and screening.3Hargreaves S Nellums L Friedland J Goldberg J Murwill P Jones L Extending migrant charging into emergency services.BMJ. 2016; 352: i685Crossref PubMed Scopus (13) Google Scholar Yet what constitutes a cost-effective approach to migrant screening and understanding what to screen for, and who, where, and when to screen, remain contentious. In The Lancet, Robert W Aldridge and colleagues4Aldridge RW Zenner D White PJ et al.Tuberculosis in migrants moving from high-incidence to low-incidence countries: a population-based cohort study of 519 955 migrants screened before entry to England, Wales, and Northern Ireland.Lancet. 2016; (published online Oct 11.)http://dx.doi.org/10.1016/S0140-6736(16)31008-XGoogle Scholar report the findings of a large retrospective cohort study of more than half a million migrants requesting a long-term entry visa to the UK (2005–12) who were screened for active tuberculosis in 15 high-incidence countries of origin before migration. Pre-entry screening data for this cohort are published elsewhere.5Aldridge RW Zenner D White PJ Prevalence of and risk factors for active tuberculosis in migrants screened before entry to the UK: a population-based cross-sectional study.Lancet Infect Dis. 2016; 16: 962-970Summary Full Text Full Text PDF PubMed Scopus (35) Google Scholar In the present study, the researchers explored what happens to migrants, free from active disease at the time of migration, after their arrival to the UK (mean follow-up 2·45 years per person). This research is timely, amid growing consensus that identification and treatment of latent tuberculosis before the disease becomes active could support elimination efforts,6Pareek M Watson JP Ormerod LP et al.Screening of migrants in the UK for imported latent tuberculosis: a multicentre cohort study and cost-effectiveness analysis.Lancet Infect Dis. 2011; 6: 435-444Summary Full Text Full Text PDF Scopus (164) Google Scholar, 7Pareek M Greenaway C Noori T et al.The impact of migration on tuberculosis epidemiology and control in high-income countries: a review.BMC Med. 2016; 14: 48Crossref PubMed Scopus (186) Google Scholar representing a shift from the historical Europe-wide approach of screening for active disease on, or soon after, arrival. Aldridge and colleagues report that migrants screened before entry pose a negligible public health risk in terms of onward transmission (only 35 assumed index cases with an estimated crude rate of five per 100 000 person-years [95% CI 4–8]) but are at risk of developing active tuberculosis after arrival to the UK, with 79·6% of cases notified after migration. The incidence of all forms of tuberculosis was lowest in the first year after arrival, and then peaked in the fourth year (222 per 100 000 person-years [95% CI 198–249]) before declining, with many cases resulting from reactivation of latent infection (301 cases with crude estimated incidence of 46 per 100 000 person-years [95% CI 42–52]). The data show, not unexpectedly, that some groups of migrants were over-represented among reactivation cases, including migrants from high-incidence countries (ie, countries with >350 cases per 100 000 people) and those with a chest radiograph compatible with tuberculosis but not bacteriologically confirmed when pre-screened in their countries of origin. Why the authors did not address the extent to which key risk factors such as socioeconomic deprivation in the host country and comorbidities (eg, HIV, diabetes mellitus) drive tuberculosis reactivation is unclear. Although these data are limited to a particular subset of migrants requesting a long-term entry visa to the UK, they have potential implications for screening policies for the wider population of migrants across Europe, and suggest that screening and treatment for latent tuberculosis in migrants from high-incidence countries before departure, and within 5 years of arrival in the host country, could strengthen control efforts. This approach is likely to be cost-effective.6Pareek M Watson JP Ormerod LP et al.Screening of migrants in the UK for imported latent tuberculosis: a multicentre cohort study and cost-effectiveness analysis.Lancet Infect Dis. 2011; 6: 435-444Summary Full Text Full Text PDF Scopus (164) Google Scholar, 7Pareek M Greenaway C Noori T et al.The impact of migration on tuberculosis epidemiology and control in high-income countries: a review.BMC Med. 2016; 14: 48Crossref PubMed Scopus (186) Google Scholar Aldridge and colleagues' data support the notion that to eliminate tuberculosis in low-burden settings multiple initiatives will be needed. The UK is one of a few European countries now screening individuals before they migrate,8Aldridge RW Yates TA Zenner D White PJ Abubakar I Hayward AC Pre-entry screening programmes for tuberculosis in migrants to low-incidence countries: a systematic review and meta-analysis.Lancet Infect Dis. 2014; 14: 1240-1249Summary Full Text Full Text PDF PubMed Scopus (69) Google Scholar and is pioneering a national strategy for latent tuberculosis testing in newly arrived migrants.9Public Health EnglandCollaborative tuberculosis strategy for England 2015–2020. Public Health England, London2015Google Scholar, 10Public Health EnglandNHS EnglandLatent TB testing and treatment for migrants: a practical guide for commissioners and practitioners. Public Health England, London2015Google Scholar We strongly support innovations in migrant screening and health-care delivery. However, policy makers need to be aware that thousands of migrants in the UK and Europe—including refugees, asylum seekers, and undocumented migrants from high-incidence countries—will completely bypass national screening programmes. Underlying all these new developments in the field of migrant health care, therefore, is the crucial need for innovative strategies to improve migrants' access to host health systems, which will ensure timely screening for not only tuberculosis, but also other common infections that disproportionately affect migrants, as well as delivery of vaccinations and affordable health care and treatment. We, for example, are exploring one-stop testing for latent tuberculosis, hepatitis B and C virus infections, and HIV through emergency departments, where a high number of migrants are thought to present. Another essential consideration is that once screened, poor follow-up and low treatment completion rates are well documented in migrant patients—particularly for latent tuberculosis—which might render screening programmes ineffective and will necessitate unique approaches.2European Centre for Disease Prevention and ControlAssessing the burden of key infectious diseases in migrant populations in the EU/EEA. European Centre for Disease Prevention and Control, Stockholm2014Google Scholar, 11Bettache N Schwartzman K Cnossen S et al.Effectiveness of post-arrival latent tuberculosis screening programs in the foreign born: systematic review and meta-analysis.Am J Respir Crit Care Med. 2012; 185: A3325Google Scholar Although the evidence base is incomplete, the European Centre for Disease Prevention and Control is currently developing much-awaited guidance on migrant screening.12European Centre for Disease Prevention and ControlEvidence-based guidance: prevention of infectious diseases among newly arrived migrants in the EU/EEA. European Centre for Disease Prevention and Control, Stockholm2015Google Scholar Aldridge and colleagues' study therefore is a welcome contribution to evolving policy discussions around improving health outcomes in migrants across Europe. We declare no competing interests. Tuberculosis in migrants moving from high-incidence to low-incidence countries: a population-based cohort study of 519 955 migrants screened before entry to England, Wales, and Northern IrelandMigrants from countries with a high incidence of tuberculosis screened before being granted entry to low-incidence countries pose a negligible risk of onward transmission but are at increased risk of tuberculosis, which could potentially be prevented through identification and treatment of latent infection in close collaboration with a pre-entry screening programme. Full-Text PDF Open Access