Infectious Disease
Spatial prediction of undetected tuberculosis in sub-Sahara Africa Haileab Fekadu Wolde* Haileab Fekadu Wolde Wolde Wolde Wolde Wolde The Kids Research Institute, Australia
Background: Tuberculosis (TB) remains a major public health challenge in sub-Saharan Africa (SSA), with many cases undetected by routine healthcare systems. This study provides the first high-resolution, multi-country geospatial analysis of undetected TB prevalence in SSA, aiming to identify high-risk areas for targeted interventions.
Methods: Data on undetected TB prevalence were extracted from 75 surveys conducted across 18 SSA countries, containing 250 unique geographic locations and screening a total of 4,321,003 individuals. Undetected TB cases were defined as the proportion of newly diagnosed TB cases identified through community surveys that had not been detected by the routine healthcare system. A Bayesian geostatistical model was used to estimate the spatial variation of undetected TB prevalence at continental, national, sub-national and pixel levels.
Results: We found that an estimated 859,333 TB cases (95% CI: 232,136–2,256,603) remained undetected. Substantial spatial variations in the prevalence of undetected TB across SSA, with notable variation at national and local levels. Predicted national prevalence ranged from 0.13 (95% CrI: 0.03, 0.19) per 1000 population in Gambia to 4.08 (0.07, 6.11) in Lesotho. Longer walking distance to health facility (in minutes) (OR = 1.12, 95% CrI: 1.06, 2.31) and higher HIV prevalence (%) (OR=1.26, CrI: 1.10, 3.25) were positively associated with increased prevalence of undetected TB.
Conclusion: This study identified significant spatial disparities in undetected TB prevalence across SSA, with healthcare accessibility and HIV prevalence as key drivers. Targeted interventions, including active case-finding, improved access to health facilities, and integrated TB and HIV care are essential to enhance case detection and reduce transmission in the identified high-risk areas.
