Zambia surge expands TB prevention for older HIV-negative household contacts

Tuberculosis remains a major public health concern in Zambia, and while coverage of tuberculosis preventive therapy (TPT) among people living with HIV has improved, uptake among HIV-negative household contacts aged ≥5 years has lagged. The evidence base suggests TPT can reduce TB incidence by up to 60% in HIV-negative individuals, but until now there has been little programmatic data from Zambia on reaching this group. Corresponding author Peter Mwaba and partners documented a focused effort to change that. The National TB Programme, supported by the TB Local Organizations Network, planned and carried out a TPT surge across 89 high TB-burden health facilities in eight project-supported provinces. The activity ran from October 2024 to 15th January 2025. After careful planning, multidisciplinary teams conducted field visits to trace household contacts of bacteriologically confirmed TB cases and to assess eligibility for TPT. The surge offered TPT to eligible household contacts regardless of HIV status or age, and also provided facility-based initiation for walk-in clients. Aggregate data were taken from facility registers and analyzed descriptively to understand reach and uptake.

The surge screened 21,890 HIV-negative household contacts for TPT eligibility. Of those screened, 21,482 (98.1%) were deemed eligible and 15,711 (74.6%) were started on TPT. Most of the screened group, 19,607 (91.8%), were over the age of 5; of these, 19,345 (98.7%) were eligible and 14,000 (72.4%) were initiated on TPT. Across all initiations, the most common regimen was three months Isoniazid + Rifapentine, which accounted for 61.2% of starts (n=9,432). The next most used regimen was six months Isoniazid at 32.6% (n=5,125). Smaller proportions began one month Isoniazid and Rifapentine (4.1%, n=638) or three months Isoniazid and Rifampicin (1.7%, n=272). These results came from the coordinated surge across 89 facilities in eight provinces and reflect facility register data collected during the October 2024 to 15th January 2025 activity.

The surge activity shows that high coverage of tuberculosis preventive therapy among HIV-negative contacts aged ≥5 years is achievable when programmes take a targeted, organized approach. Key elements included planning, stakeholder engagement, multidisciplinary teams, and community-driven contact tracing to find household contacts of bacteriologically confirmed TB. By offering TPT regardless of HIV status or age and by making initiation available both through field visits and at health facilities for walk-ins, the programme reached large numbers of eligible people. These findings address a gap in programmatic evidence for rolling out TPT to older HIV-negative contacts in Zambia and similar high-burden settings. They support the argument that routine TPT delivery should be expanded to include all high-risk household contacts to help accelerate TB prevention efforts in places with heavy TB burdens.