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

Abstract

In 1999, the World Health Organization (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-γ 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 individuals, as this constitutes an enormous source of potential active tuberculosis.

Global tuberculosis prevention: should we start from the beginning?

“…The analysis combining TST and IGRAs found a prevalence of LTBI of 25.2% (IGRAs-based prevalence) and 27.1% (>10 mm TST-based prevalence). Therefore, COHEN et al [24] in this study found global LTBI prevalence similar to that reported by HOUBEN and DODD [19] in 2016, with an estimate of 23%, but lower compared with that 32% estimated by WHO in 1999. The higher LTBI prevalence estimated by WHO can be attributed to the epidemiology of 1999, when TB incidence was higher with consequently higher M. tuberculosis transmission rates.…”

“…The manuscript of COHEN et al [24], entitled "The global prevalence of latent tuberculosis: a systematic review and meta-analysis", published in this issue of the European Respiratory Journal, describes LTBI prevalence worldwide. Different from previous studies that used mathematical models, they systematically collated the current evidence published in scientific journals and provided quantitative estimates with a meta-analysis approach.…”

Infección tuberculosa latente en personal de salud de las Américas

“…En un metaanálisis que estimó la prevalencia global de ITLB a partir de 88 estudios de 36 países, publicados entre 2005 a 2018 (Cohen et al) 21 , la prevalencia de ITBL con prueba de interferón gamma fue de 24.8 % (IC95 % 19.7-29.9 %) y con PPD fue de 21.2 % (IC95 % 17.9-24.2 %). Al comparar estos resultados con lo encontrado en esta revisión, se observó que del total de publicaciones nueve de ellas reportaron prevalencias mayores a la estimada en esa revisión sistemática, cuatro publicaciones tenían prevalencias similares y solamente una de ellas tenía una prevalencia menor.…”

“…Al realizar la comparación entre las dos revisiones sistemáticas, se observó que la carga de ITBL sigue siendo mayor en personal de salud en comparación con la población general, ya que la revisión sistemática y metaanálisis de la prevalencia de ITBL en trabajadores de salud de países con más carga por TB, obtuvo una prevalencia global de 47 % (IC95 % 34-60) y en Brasil de 37 % (IC95 % 17-56), siendo mucho mayor de lo reportado por Cohen 21 .…”

Advancing new diagnostic tests for latent tuberculosis infection due to multidrug-resistant strains of Mycobacterium tuberculosis — End of the road?

“…Latent tuberculosis infection (LTBI) is defined by the World Health Organization (WHO) as "a state of persistent immune response to stimulation by Mycobacterium tuberculosis antigens without evidence of clinically manifested active TB" (WHO, 2019). An estimated 1.8 billion people worldwide have LTBI, with wide variations in LTBI rates across countries (Houben and Dodd, 2016;Knight et al, 2019;Huaman and Sterling, 2019;Cohen et al, 2019). LTBI can be due to infection with either drug-sensitive or drugresistant M. tuberculosis (Mtb) strains.…”