The scale of the analysis is what sets it apart. Most previous research on migrant tuberculosis screening has focused narrowly on detecting active disease or on modelling the cost-effectiveness of screening for tuberculosis infection, the asymptomatic stage in which the bacteria persist without causing illness. Few studies have examined large-scale national programmes, reported age-stratified yields, or traced the full cascade of preventive treatment from diagnosis through completion. By linking screening results collected by all 25 Municipal Public Health Services to national notification data, the researchers were able to follow nearly 150,000 individuals from the moment of their first chest X-ray or infection test through to treatment outcomes.

The headline finding concerns the stark difference between two migrant categories. Among 87,511 immigrants, defined as labour migrants, international students and others arriving through regular channels, entry screening detected 69 cases of active tuberculosis, a yield of 79 cases per 100,000 people screened. Among 61,703 asylum seekers, screening identified 170 cases, a yield of 276 per 100,000, more than three times higher. The gap reflects both the higher tuberculosis burden in the countries from which asylum seekers predominantly arrive, including Eritrea, Afghanistan, Somalia and Algeria, and the adverse conditions of the migration journey itself, which can reactivate dormant infection through malnutrition, stress and crowding.

Country-level yields sharpened the picture further. Among asylum seekers, screening prevalence exceeded World Health Organization incidence estimates for their countries of birth in every case except Afghanistan, with the highest yields recorded among people from Sierra Leone at 888 per 100,000, Eritrea at 704, Somalia at 581, the Gambia at 562 and South Sudan and Sudan at 519. Among immigrants, by contrast, prevalence at entry was lower than WHO estimates for every country contributing more than five detected cases, with the highest yields among those from Indonesia at 291 per 100,000 and the Philippines at 241, and comparatively low yields among immigrants from India and South Africa. The researchers interpret this as evidence of the healthy migrant effect: people who migrate for work or study tend to be younger, healthier and more affluent than the general population of their country of origin, and therefore carry a lower tuberculosis risk than WHO national averages imply.

Perhaps the most consequential finding for clinical practice is the weakness of symptom-based detection. Of the 202 migrants diagnosed with pulmonary tuberculosis through screening, only 27.2 percent reported a cough, the symptom that anchors most passive case-finding strategies. The proportion was lower still among immigrants, at 13.8 percent, compared with 32.6 percent among asylum seekers. In other words, nearly three in four screen-detected pulmonary cases would have been missed by symptom screening alone. This aligns with a growing body of evidence on what the WHO now terms asymptomatic tuberculosis, and with community prevalence surveys in high-incidence settings showing that roughly half of bacteriologically confirmed pulmonary cases report no suggestive symptoms. Because such individuals can transmit the infection unknowingly for months, the study argues that systematic radiological screening retains clear value for populations at elevated risk, catching disease before symptom onset and before onward transmission occurs.

The diagnostic profile of detected cases supports the programme’s technical rigour. Overall, 56.5 percent of the 239 screen-detected tuberculosis cases were bacteriologically confirmed, rising to 63.9 percent among pulmonary cases, and 44 individuals had acid-fast bacilli visible on microscopy, indicating potentially infectious disease. Only two cases involved multidrug-resistant tuberculosis. Treatment outcomes, however, revealed a care gap: 92.8 percent of immigrants with tuberculosis were recorded as cured or having completed treatment, compared with 81.2 percent of asylum seekers, a difference driven mainly by loss to follow-up, including five asylum seekers who never initiated treatment and others who left the country before completing therapy. The authors point to the need for tailored support and stronger cross-border collaboration to maintain continuity of care for mobile populations.

The study’s second major contribution is its analysis of tuberculosis infection screening among more than 20,000 immigrants, the first time this component has been included in the Dutch national evaluations. Infection prevalence rose sharply with age: 0.6 percent among children under 12, 4.4 percent among adolescents aged 12 to 17, and 12.9 percent among adults screened from the highest-incidence countries. Among adults, prevalence exceeded 20 percent for immigrants from Kenya, Nigeria and Zimbabwe, while remaining markedly lower at 4.9 percent for those from South Africa. The Dutch algorithm, which uses an initial tuberculin skin test followed by confirmatory interferon gamma release assay when the skin test measures 10 millimetres or more, likely suppressed false positives; only about half of adults with a positive skin test had infection confirmed by IGRA, and confirmation rates fell below 10 percent in young children, where prior BCG vaccination may drive false-positive skin reactions.

The cascade of preventive treatment offered encouraging evidence that a well-structured public health system can convert infection diagnoses into completed therapy. Preventive treatment was initiated in 68.6 percent of infected children under 12, 85.2 percent of adolescents and 70.3 percent of adults, and among those who started, completion exceeded 92 percent in every age group, most commonly with a short three-month regimen of rifampicin and isoniazid. Combining initiation and completion, between 64.6 and 81.5 percent of infected individuals across age groups successfully finished preventive therapy, figures that outperform pooled international estimates of roughly 52 percent. The weaker uptake among young children, attributed largely to parental reluctance to medicate healthy children, combined with their very low infection prevalence, prompted the National TB Guideline Committee to recommend exempting immigrant children under 12 from mandatory screening, a concrete example of epidemiological data reshaping national policy.

The findings arrive at a moment when tuberculosis control in Europe increasingly depends on migrant-focused strategies. In 2024, 37.6 percent of people notified with tuberculosis in the EU and European Economic Area were of foreign origin, a share exceeding 80 percent in several countries including the Netherlands, which recorded just 4.3 cases per 100,000 population overall. The study supports maintaining divergent screening thresholds, with asylum seekers screened from countries with incidence of 50 per 100,000 or above and immigrants from countries at 100 or above, and it strengthens the economic case for infection-based follow-up screening, which Dutch modelling suggests is more cost-effective than repeated chest X-rays for asylum seekers. Emerging tuberculosis-antigen skin tests may further improve specificity and cost-effectiveness. The authors conclude that targeted screening of migrants, combining disease detection with infection testing and high-quality preventive treatment, is a core and demonstrably effective component of tuberculosis elimination in low-incidence settings, provided that screening strategies continue to be refined with timely, age-specific and group-specific national data.

Subject of Research: National evaluation of tuberculosis disease and tuberculosis infection screening among migrants in the Netherlands from 2019 to 2023

Article Title: Tuberculosis disease and infection screening among migrants in the Netherlands 2019–2023: a national retrospective observational study

Article References: de Vries, G., Mulder, A., Spruijt, I., Huisman, E., Schimmel, H., Siebers, M., Vrubleuskaya, N., Zandbelt-Smits, M., van Gageldonk-Lafeber, R., & van den Hof, S. (2026). Tuberculosis disease and infection screening among migrants in the Netherlands 2019–2023: a national retrospective observational study. The Lancet Regional Health – Europe, 70, Article 101856. https://doi.org/10.1016/j.lanepe.2026.101856

Image Credits: AI Generated

DOI: 10.1016/j.lanepe.2026.101856

Keywords: tuberculosis, migrant health, screening, asylum seekers, tuberculosis infection, preventive treatment, public health, Netherlands, epidemiology, low-incidence countries, chest X-ray, IGRA