Integrating Early Tuberculosis States Into Contact Management in Peru

Tuberculosis (TB) is now understood to exist on a spectrum from TB infection to active TB disease. While World Health Organization guidelines target TB infection and TB disease, they overlook individuals with early TB in the middle of this spectrum.

To evaluate chest radiograph (CR)-guided screening strategies among household contacts (HHCs) of patients with TB in a high-burden setting.

This decision analytical model was constructed from June 1 to November 31, 2024. Community-based care in an environment with high TB burden and limited resources was used as the setting in Lima, Peru. Participants included a hypothetical cohort of 1000 HHCs with positive results of a tuberculin skin test and negative results of a sputum culture who were cleared of TB disease based on a clinician's evaluation. The hypothetical cohort was based on the clinical and demographic features of a cohort studied between September 1, 2009, and August 29, 2012.

Strategy 1 included CR screening to rule out TB disease followed by TB preventive therapy for all; strategy 2, CR screening with treatment for TB disease for those with abnormal CR findings and TB preventive therapy for those without; and strategy 3, observation without pharmacological intervention. We modeled 6 intervention scenarios by applying strategies 1 and 2 to the entire HHC population, to HHCs younger than 35 years, and to HHCs younger than 19 years (Peru's national TB policy).

TB cases averted, serious adverse events (SAEs), and drug resistance.

A simulated cohort of 1000 HHCs with age and clinical status distributions was based on a previously published cohort of 12 767 TB HHCs in Lima, Peru. Of these, 7661 (60.0%) were male, 4212 (33.0%) were younger than 15 years, and 444 (3.4%) developed TB during 1 year of follow-up. Strategy 2 applied to all HHCs reduced TB cases by 71% to 81%, outperforming strategy 1 applied to all HHCs, which reduced cases by 49% to 69%. Strategy 2 reduced acquired isoniazid resistance but increased SAEs. When both strategies were restricted to HHCs younger than 19 years, strategy 2 reduced TB cases by 42% to 50%. Expanding treatment to older adults further reduced cases but also increased SAEs (19-22 additional SAEs).

In this model of TB HHC management, CR-guided identification and treatment of early TB was more effective than universal isoniazid preventive therapy, especially in children and young adults. Trade-offs between benefit and harm must be carefully considered in older adults.