Data from: The global prevalence of latent tuberculosis: a systematic review and meta-analysis

In 1999, the WHO estimated that one-third of the world‟s population had
latent tuberculosis infection (LTBI) which was recently updated to
one-fourth. However, this is still based on controversial assumptions in
combination with tuberculin skin test (TST) surveys. Interferon-gamma
release assays (IGRAs) with a higher specificity than TST have since been
widely implemented, but never used to estimate the global LTBI prevalence.
We conducted a systematic review and meta-analysis of LTBI estimates based
on both IGRA and TST results published between 2005 and 2018. Regional and
global estimates of LTBI prevalence were calculated. Stratification was
performed for low, intermediate and high TB incidence countries and a
pooled estimate for each area was calculated using a random effects model.
Among 3280 studies screened, we included 88 studies from 36 countries with
41 IGRA (n=67 167) and 67 TST estimates (n=284 644). The global prevalence
of LTBI was 24.8% (95% CI: 19.7-30.0%) and 21.2% (95% CI: 17.9-24.4%)
based on IGRA and a 10 mm TST cut-off respectively. The prevalence
estimates correlated well to WHO incidence rates (Rs=0.70,
p<0.001). In the first study of the global prevalence of LTBI
derived from both IGRA and TST surveys, we found that one-fourth of the
world‟s population is infected. This is of relevance as both tests,
although imperfect, are used to identify individuals eligible for
preventive therapy. Enhanced efforts are needed targeting the large pool
of latently infected as these individuals continuously constitutes an
enormous source of potential active TB.