Background
• Tuberculosis continues to be a public health concern in high-income countries |
• Tuberculosis burden in high-income countries is primarily amongst the foreign-born, migrant population |
• The reasons underlying this burden are the interaction of migration from high TB burden countries and the reactivation of remotely acquire latent tuberculosis infection in the first five years after arrival |
• Genotyping data suggests that there is relatively little transmission in migrant communities in the receiving country |
• Methods of TB control in migrant population have historically focused on identifying active tuberculosis but the yields for this remain relatively low |
• Screening migrants for latent tuberculosis infection may have a higher yield although implementation may be difficult |
• The health economics of screening migrants for active and/or latent tuberculosis is a topic of much debate |
• Targeted pre-arrival screening for active TB and post arrival screening for latent tuberculosis infection in migrants from intermediate/high TB burden settings may provide the most cost-effective solution |
• Implementation of programmatic screening is limited by uptake, acceptance and completion of therapy |
Tuberculosis epidemiology in high-income countries
Migration and reactivation of latent TB infection: key drivers of tuberculosis in migrants in high-income countries
Understanding the scale and nature of migration to high-income countries
Reactivation of latent TB infection in determining TB burden in migrants
Active TB disease in migrants on arrival in the receiving country
High prevalence of latent TB infection and risk of progression to active disease
Using molecular genotyping to distinguish reactivation of latent TB and recent transmission of active TB in migrants
Tuberculosis control with a special focus on migrants
Migrant screening practices and their outcomes in high-income countries
Screening methodology | ||
---|---|---|
Screening for active tuberculosis | Screening for latent tuberculosis infection | |
Screening tool used | Chest x-ray | Tuberculin skin test |
Interferon gamma release assay | ||
Screening location | Pre-arrival | Post-arrival |
At arrival | ||
Post-arrival | ||
Strengths | Able to identify active TB | Identifies latent TB before reactivation occurs |
Able to identify infectious individuals | Can be built into community programmes | |
Can be integrated into immigration processes | Targeted screening likely to be cost-effective | |
Weaknesses | Low yields for active TB | Programmatically difficult to implement |
Uncertain cost-effectiveness (unless screening targeted) | Numbers accepting and completing treatment may be suboptimal | |
Does not identify patients with latent TB who can go on to reactivate |