From Contact Screening to Preventive Treatment Provision; Progress and Bottlenecks in High Tuberculosis Burden Settings.

Background: Tuberculosis (TB) preventive treatment (TPT) remains poorly utilized (5.4%) among eligible household contacts in Pakistan despite programmatic expansion. A critical programmatic knowledge gap exists regarding the magnitude and distribution of pre-initiation attrition among household (HH) contacts, including which stages of the care cascade and health facility types at which losses occur in Pakistan. This study aimed to quantify attrition of HH contacts of bacteriologically positive (B-pos) TB patients before TPT initiation at different stages of the care cascade. Methods: This retrospective cohort evaluated programmatic TB data from HH contacts of B-pos pulmonary TB patients managed through Public-Private Mix (PPM) facilities in 28 districts of Pakistan from January-July 2025. Contacts were verbally screened, assessed using chest radiography to exclude TB disease, and eligible individuals were offered TPT. Results: Among 20,290 index TB patients, 77,771 HH contacts were identified. Of all identified HH contacts, 55% (42,410/77,771) underwent verbal screening. Among those screened, 32% (13,395/42,410) proceeded to chest X-ray screening and 98% (13,145/13,395) started TPT. Around 4% (1,505) were identified as presumptive TB cases and 52% (792/1,505) were diagnosed with TB. Substantial pre-treatment attrition occurred at two critical stages: 45% prior to verbal screening and 63% prior to X-ray screening. Children aged 0-4 years had the lowest TPT initiation (13.1%), despite being a high-risk group. Conclusion: Substantial losses before TPT initiation occur during contact screening and disease exclusion stages, indicating programmatic challenges requiring targeted operational strategies. Only 16.9% of household contacts completed the care cascade, highlighting a major missed opportunity for TB prevention.