Feasibility, enablers and challenges of using timeliness metrics for household contact tracing and TB preventive therapy in Pakistan.

Introduction: Screening household contacts of TB patients and providing TB preventive therapy (TPT) is a key intervention to end the TB epidemic. Global and timely implementation of TPT in household contacts, however, is dismal. We adapted the 7-1-7 timeliness metric designed to evaluate and respond to infectious disease outbreaks or pandemics, and assessed the feasibility, enablers and challenges of implementing this metric for screening and management of household contacts of index patients with bacteriologically-confirmed pulmonary TB in Karachi city, Pakistan.

Methods: We conducted an explanatory mixed methods study with a quantitative component (cohort design) followed by a qualitative component (descriptive design with focus group discussions).

Results: From January-June 2023, 92% of 450 index patients had their household contacts line-listed within seven days of initiating anti-TB treatment ("first 7"). In 84% of 1342 household contacts, screening outcomes were ascertained within one day of line-listing ("next 1"). In 35% of 256 household contacts eligible for further evaluation by a medical officer (aged ≤5 years or with chest symptoms), anti-tuberculosis treatment, TPT or a decision for no drugs was made within seven days of symptom screening ("second 7"). The principal reason for not starting anti-tuberculosis treatment or TPT was failure to consult a medical officer: only 129(50%) of 256 contacts consulted a medical officer. Reasons for poor performance in the "second 7" component included travel costs to see a medical officer, loss of daily earnings and fear of a TB diagnosis. Field staff reported that timeliness metrics motivated them to take prompt action in household contact screening and TPT provision and they suggested these be included in national guidelines.

Conclusions: Field staff found "7-1-7" timeliness metrics to be feasible and useful. Integration of these metrics into national guidelines could improve timeliness of diagnosis, treatment and prevention of TB within households of index patients.