Scaling-up tuberculosis preventive therapy to HIV-negative contacts of bacteriologically confirmed TB cases aged 5 years and above - Lessons from a tuberculosis preventive therapy surge activity in Zambia.

Abstract

While tuberculosis preventive therapy (TPT) coverage among people living with HIV in Zambia has improved, uptake among HIV-negative contacts aged ≥5 years remains low. Despite evidence showing that TPT can reduce TB incidence by up to 60% in HIV-negative individuals, there is a paucity of evidence on programmatic rollout to this population in Zambia and the region. We present programme data from a TPT surge aimed at increasing uptake among ≥5 years old HIV-negative household TB contacts. The National TB Programme, with support from the TB Local Organizations Network, conducted a TPT surge in 89 high TB-burden facilities across eight project supported provinces in Zambia from October 2024-15th January 2025. After a thorough planning phase, multidisciplinary teams conducted field visits for contact tracing and initiated TPT for eligible household contacts of bacteriologically confirmed TB.. Facility-based TPT initiation was provided for walk-in clients. We collected and analyzed aggregate data from facility registers. A total of 19,371 HIV-negative contacts aged ≥ 5 years were screened: 99.9% (n = 19,344) were eligible for and offered TPT. Of these, 72.4% (n = 14,000) were initiated on TPT, 2.0% (n = 385) refused and 26.2% (n = 4,959) were not initiated on treatment due to unavailability of their preferred regimen. The start of the surge was associated with an immediate 47.7% points increase in TPT coverage (p = 0.001). Overall, 63.7% (n = 8,917) were initiated on three-months Isoniazid+Rifapentine, followed by six-months Isoniazid (30.2%, n = 4226); one-month Isoniazid+Rifapentine (4.5%, n = 625) and on three-months Isoniazid+Rifampicin (1.7%, n = 232). The surge demonstrated that TPT can be rolled out to ≥5 years old HIV-negative TB contacts with high initiation rates achieved. This is achievable through targeted implementation, stakeholder engagement, and community-driven approaches. These findings underscore the feasibility of extending TPT to all TB contacts, regardless of HIV status or age, to accelerate TB prevention efforts in high-burden settings like Zambia.