Migration and tuberculosis in the UK: targeting screening for latent infection to those at greatest risk of disease.

Active tuberculosis (TB) in the UK predominantly affects the non-UK born, but is generally not manifest at the time of UK entry. Strategies to detect latent TB infection (LTBI) in this population are, therefore, important. To date, targeted screening has focused on TB risk estimates based on the incidence in the country of origin. Using TB incidence in the UK and migration data, we estimated the numbers needed to be tested and treated for LTBI to prevent one case of TB disease. Numbers were the lowest in Somalian and the highest in South African and Filipino migrants, which contrasts with TB rates in these countries. Targeting screening on the basis of incidence in the UK may thus improve effectiveness.