Setting: Primary care clinic serving a high tuberculosis (TB) and human immunodeficiency virus (HIV) prevalence community in South Africa.
Objective: To evaluate a program combining TB and HIV contact investigation with tracing of individuals lost to TB or HIV care.
Design: Contacts were offered home-based HIV testing, TB symptom screening, sputum collection and referral for isoniazid preventive therapy (IPT). Effectiveness was assessed by the number needed to trace (NNT).
Results: Only 419/1197 (35.0%) households were successfully traced. Among 267 contacts, we diagnosed 27 new HIV cases (10 linked to care) and two TB cases (both initiated treatment) and three started IPT. Of 630 patients lost to care, 132 (21.0%) were successfully traced and 81 (61.4%) re-engaged in care. The NNT to locate one individual lost to care was 4.8 (95%CI 4.1-5.6), to re-engage one person in care 7.8 (95%CI 6.4-9.7), to diagnose one contact with HIV 44.3 (95%CI 30.6-67.0), to link one newly diagnosed contact to HIV care 120 (95%CI 65.3-249.2) and to find one contact with active TB and initiate treatment 599 (95%CI 166.0-4940.7).
Conclusion: The effectiveness of this contact tracing approach in identifying new TB and HIV cases was low. Methods to optimize contact investigation should be explored and their cost-effectiveness assessed.