Tuberculosis in Pakistan

Between March 2018 and May 2019, a population-based survey was conducted in Karachi, Pakistan, to estimate the prevalence of adult pulmonary tuberculosis (TB) and M. tuberculosis infection in children. Using cluster-based random sampling, the study compared areas with and without prior active case finding (ACF) interventions. Participation was high overall, especially among adult women (90.1%), though lower among men (67.0%). The large sample—over 34,000 adults and 1,500 young children—provided a robust basis for estimating TB prevalence and infection risk.

The findings revealed a lower prevalence of pulmonary TB in areas with previous ACF efforts. The overall prevalence among adults was estimated at 275 per 100,000, but this was notably lower in the prior ACF zones (183 per 100,000) compared to zones without prior interventions (288 per 100,000). A sex-specific trend also emerged: TB prevalence in no prior ACF zones was significantly higher in men than women, while in prior ACF areas, the burden was more evenly distributed between sexes. This suggests that ACF may help reduce disparities and lower overall TB rates.

Despite these promising trends, the study highlighted persistent challenges in TB diagnosis and care. While over 10% of adults were eligible for sputum testing, submission rates were higher in prior ACF areas. However, among those diagnosed with TB, only 26% began treatment, and 57% could not be contacted or refused follow-up. Additionally, a significant proportion of microbiologically confirmed cases were Xpert Ultra ‘trace positive’ only, complicating diagnostic clarity and treatment decisions.

The child M. tuberculosis infection survey further underscored the potential community-level impact of ACF. Among children aged 2 to 4 years, the estimated annual risk of infection (ARTI) was significantly lower in prior ACF zones (0.6%) compared to those without prior interventions (1.1%). This suggests that targeted case-finding in adults may contribute to reducing transmission risk to children. Together, these findings advocate for the continued implementation and expansion of ACF strategies, while also calling attention to the urgent need to improve linkage to care and treatment uptake for those diagnosed.

Source: Khan, P.Y., Paracha, M.S., Grundy, C., Madhani, F., Saeed, S., Maniar, L., Dojki, M., Page-Shipp, L., Khursheed, N., Rabbani, W. and Riaz, N., 2024. Insights into tuberculosis burden in Karachi, Pakistan: A concurrent adult tuberculosis prevalence and child Mycobacterium tuberculosis infection survey. PLOS global public health, 4(8), p.e0002155.