The Preventing TB Overseas Pilot Study (PTOPS): Voluntary Latent Tuberculosis Infection Testing and Treatment for US-Bound Immigrants in Vietnam

Abstract

In 1989, the United States declared a goal to eliminate tuberculosis (TB) by 2010, with elimination defined as <1 case per million. In 2019, the US reported 27 cases per million with 70% of cases occurring in the foreign-born. Over 80% of cases were reactivation of latent TB infection (LTBI) acquired prior to US arrival. Strategies to address LTBI have been suboptimal and innovations are critical to reach TB elimination. Currently, the pre-arrival immigrant medical examination focuses on identifying TB disease. To address LTBI in immigrants, a potential strategy is to offer voluntary LTBI testing using an interferon-gamma release assay (IGRA) and 3 months of weekly isoniazid and rifapentine (3HP) treatment during the examination. A prospective cohort study was conducted among US-bound immigrant visa applicants undergoing the examination in Vietnam. This study assesses uptake, acceptability, and factors associated with three different points of the LTBI care cascade. Of 5311 visa applicants recruited, 2438 (46%) consented; 2276 had an IGRA processed, and 484 (21%) tested positive. Among 452 participants eligible for 3HP, 304 (67%) initiated treatment and 268 (88%) completed treatment. Being female, aged 18-35, bacille Calmette-Guerin (BCG) vaccinated, currently in school or employed, knowing a family member with TB, or having a private mode of transportation were associated with test acceptance. Immigrating with family was associated with treatment and immigrating >2 months was associated with testing and treatment. No predictors merged for treatment completion. LTBI prevalence was high; however, test acceptance was low. The proportion initiating treatment overseas was similar to immigrant populations in the United States. Among those initiating treatment overseas, the proportion completing treatment was high at 88%. The study demonstrates that using the overseas medical examination to provide voluntary LTBI testing and treatment should be considered to address LTBI in US-bound immigrants to advance TB elimination efforts.