Pareek M. Lancet Infect Dis.2011;doi:10.1016/S1473-3099(11)70069-X.
The prevalence of latent tuberculosis infection varied
by gender, age and the country of origin among immigrants in the United
Kingdom. Researchers, therefore, suggest screening immigrants for latent
tuberculosis infection because it is a cost-effective way to prevent future
cases of active tuberculosis, according to Ajit Lalvani, MD, and
“UK national guidance for which groups to screen
excludes most immigrants with latent infection, and our analysis suggests that
policy could be modified in centers undertaking or considering the
implementation of one-step interferon-gamma release-assay to substantially
reduce TB incidence while remaining cost-effective,” Lalvani, a professor
Tuberculosis Research Unit of the Imperial College
London, and colleagues wrote.
The researchers pooled demographic and test result data
on 1,229 UK immigrants, aged 35 years and younger, across three centers in the
UK that used interferon-gamma release-assay between 2008 and 2010. Logistic
regression analysis was used to assess the cost-effectiveness of screening at
different levels of TB incidence in countries of origin.
Data indicated a high prevalence of positive latent TB
infection among 20% of immigrants (95% CI, 18-22). Positive screening results
were associated with male gender (P=.046), age (P,.0001) and
increased TB incidence in countries of origin (P=.0006). Specifically,
32% of immigrants originated from Pakistan and 26% from India.
Screening immigrants from countries with a TB incidence
of more than 250 cases per 100,000 and in countries with a more than 150 cases
per 100,000 were the two most cost-effective strategies, according to the
guidelines are developed for screening of latent TB
with new techniques (such as [interferon-gamma release-assay]), they will need
to quantitatively integrate the prevalence of latent infection in immigrant
populations from different regions to formulate policy that cost-effectively
improves TB control and prevention,” the researchers wrote.
Disclosure: This research was funded by Medical Research Council
and Wellcome Trust.