This study re-estimates the global burden of latent tuberculosis infection (LTBI) using mathematical modeling, updating an old estimate that claimed one-third of the world population was infected. The researchers used a combination of direct estimates from LTBI surveys (1950-2011) and indirect estimates from World Health Organization (WHO) data on smear-positive TB prevalence (1990-2014). They applied Gaussian process regression to generate annual risk of infection (ARI) for country-years without data and to account for uncertainty. The estimated global prevalence of LTBI in 2014 was 23.0% (95% UI: 20.4%-26.4%), affecting approximately 1.7 billion people. The WHO South-East Asia, Western Pacific, and Africa regions had the highest prevalence, accounting for about 80% of cases. The study also estimated that around 56 million individuals were recently infected, with 11% carrying isoniazid-resistant strains. If no new infections occur after 2015, the current LTBI burden would lead to TB incidence of 16.5 per 100,000 per year in 2035 and 8.3 per 100,000 per year in 2050, far exceeding the End TB Strategy targets. The findings highlight the urgent need for improved diagnosis and treatment of LTBI to achieve the 2050 goal of eliminating TB.This study re-estimates the global burden of latent tuberculosis infection (LTBI) using mathematical modeling, updating an old estimate that claimed one-third of the world population was infected. The researchers used a combination of direct estimates from LTBI surveys (1950-2011) and indirect estimates from World Health Organization (WHO) data on smear-positive TB prevalence (1990-2014). They applied Gaussian process regression to generate annual risk of infection (ARI) for country-years without data and to account for uncertainty. The estimated global prevalence of LTBI in 2014 was 23.0% (95% UI: 20.4%-26.4%), affecting approximately 1.7 billion people. The WHO South-East Asia, Western Pacific, and Africa regions had the highest prevalence, accounting for about 80% of cases. The study also estimated that around 56 million individuals were recently infected, with 11% carrying isoniazid-resistant strains. If no new infections occur after 2015, the current LTBI burden would lead to TB incidence of 16.5 per 100,000 per year in 2035 and 8.3 per 100,000 per year in 2050, far exceeding the End TB Strategy targets. The findings highlight the urgent need for improved diagnosis and treatment of LTBI to achieve the 2050 goal of eliminating TB.