XClose

UCL Institute of Health Informatics

Home
Menu

Preventing Tuberculosis in Migrant Populations

Principal Investigator: Rob Aldridge
Investigators: Andrew Hayward, Ibrahim Abubakar

The Challenge

Tuberculosis (TB) remains an important public health problem. While specific challenges exist for managing TB in the homeless population the largest numbers of cases originate from individuals born outside the UK. If migrants come from countries where there is much higher rates of TB, they can develop the disease several years following their arrival.

The Research

Screening of migrants has been ongoing for a long time, with examination by chest X-Ray upon airport arrival being abandoned in favour of pre-entry screening. In this system, anyone from a high tuberculosis incidence country applying for a visa to stay in the UK for longer than six months is screened in their home country. This research took data from 15 countries taking part in pilot pre-entry since 2005 and analysed their longer term follow-up in the UK. This was not straightforward as no unique identifier was available to link different datasets. A new method based on a probability of match to a case was validated in order to track the outcomes.

The Results

Working with Public Health England and Imperial College London, the Farr Institute researchers used the original pre-screening data cross-matched with the UK TB register. It was found migrants had an increased personal risk of TB but there were very low rates of onward transmission of the disease. This indicated that the healthcare system was being accessed for testing and treatment with good outcomes.

The Impact

The work provided an important public health message on an important disease prevention system that works. It also highlighted that common views in the media about migrants spreading TB were incorrect. The fact that migrants have higher ongoing personal risk created a recommendation for using additional blood tests that can detect latent tuberculosis (people who are infected with the bacterium without symptoms). These tests have potential for also finding the majority of people who develop TB post-arrival.

Foe more information: Aldridge et al (2016) Lancet Infect Dis. Mar 21. S1473-3099(16)00072-4; Aldridge et al. (2015) PLoS One 10:e0136179.