The Spot-to-Tent Onion Model: a scalable strategy for layered tuberculosis contact tracing in high-burden settings

Tuberculosis (TB) remains a significant global health challenge, particularly in Nigeria, which harbours one of the highest TB burdens worldwide. Traditional TB control methods have proven insufficient, necessitating innovative approaches like the Spot-to-Tent Onion Model (STOM) project in Akwa Ibom State. This paper aimed to demonstrate the utility of STOM in enhancing TB case finding and initiating TB Preventive Therapy (TPT) within the community. Implementation data were routinely captured between January and September 2023, including stakeholder engagements and training of community health workers in TB contact investigation, active TB household contact investigation, TB screening within a 2 km radius of index patient location, and placement of eligible clients on TPT. Data from health records were analyzed to track TB case finding and initiation of TPT. All 4,665 index TB cases diagnosed within the period of implementation had their contacts investigated for TB achieving a 100% index patient coverage. Of the total contacts screened, 17,244 presumptive TB were identified and evaluated with a total of 970 TB cases diagnosed. This gave an overall TB yield of 5.63%. Within the period, seven drug-resistant TB cases were diagnosed and placed on treatment. Out of 21,846 eligible contacts, 10,337 (47%) commenced TPT, marking a considerable enhancement in the state’s TPT uptake. Through community-based approaches, STOM demonstrates significant potential in improving TB case finding and prevention in high-burden settings. Leveraging community health workers and targeted strategies has proven effective, underscoring the need for integrating such innovative methods into national TB control strategies.