Consolidating Cause-of-Death Evidence for Children and Adolescents through an Updated Systematic Review and Known Investigator-Tracing

<p><b><span>Introduction: </span></b></p> <p><span>Reliable age- and cause-specific mortality estimates for children and adolescents depend on the availability and comparability of empirical cause-of-death (COD) data. In many high-mortality settings, incomplete civil registration and fragmented surveillance systems limit such data. This review aims to identify and consolidate COD evidence for individuals aged 0–19 years.</span></p> <p><b><span>Methods:</span></b></p> <p><span>We conducted a systematic review of empirical COD studies for 0–19-year age groups in high-mortality settings with incomplete or no vital registration (VR) systems. Bibliographic database research was completed in February 2023 and supplemented by investigator-led identification. Eligible studies reported surveillance data from 1980 onwards, applied standardized COD ascertainment and met predefined criteria for population coverage, and data quality. Screening and data extraction were performed independently by two reviewers using machine-learning–assisted workflows and COD were harmonized to ensure comparability across studies.<b></b></span></p> <p><b><span>Results:</span></b></p> <p><span>We identified 77 eligible studies contributing 368 data points across age groups. Data availability was greatest for 1–59 months and sparse for older children and adolescents. Most evidence originated from South Asia and Eastern and Southern Africa. Leading causes varied by age group, with infectious causes predominating in under-5 and injuries more prominent at older ages. Verbal autopsy (VA) was the predominant method of COD ascertainment, accounting for 89% of data points.<b></b></span></p> <p><b><span>Conclusions</span></b><span>:</span></p> <p><span>This review consolidates empirical COD data for 0-19 years in high mortality settings, supporting more accurate and reproducible mortality estimation where VR is limited, while highlighting persistent data gaps and the need for expanded population based, nationally representative mortality surveillance.</span></p>