Abstract
<title>Abstract</title> <p> <bold>Background</bold> TB-HIV co-infection disproportionately affects children in sub-Saharan Africa. Scale-up of PMTCT, ART, and TB Preventive Therapy (TPT) aims to reduce this burden. This study estimated HIV prevalence among TB-registered children aged < 15 years across ten high-burden Tanzanian regions (2018–2023) and identified factors associated with HIV co-infection. <bold>Methods</bold> A cross-sectional retrospective review of records was conducted using secondary data extracted from the National TB and Leprosy System, District Health Information System-2 Electronic TB and Leprosy (DHIS2-eTL). All children aged < 15 years who were diagnosed with TB and had documented HIV status across ten regions with high a TB burden between January 2018 and December 2023 were included. Binary logistic regression was used to identify factors associated with HIV co-infection, and results are reported as adjusted odds ratios (aOR) with 95% confidence intervals (CI) at 5% statistical significance <bold>Results</bold> Among 25,449 children with TB, 3,667(14.4%) had a documented HIV-positive status. HIV prevalence declined markedly from 28.5% in 2018 to 8.9% in 2023 (p < 0.001). Pediatric TB-HIV co-infection increased with age: 9.0% in children aged below 5 years, 17.7% in those aged 5–9 years, and 22.6% in those aged 10–14 years (p < 0.001), with noticeable regional variations. After multivariable adjustment, older age groups (aOR = 2.32 95% CI 2.11–2.55 and 2.99 95% CI 2.72–3.29 for 5–9 and 10–14 years, respectively), residence in Njombe (aOR = 1.73, 95% CI 1.46–2.04), Mbeya (aOR = 1.53, 95% CI 1.31–1.78), and Iringa (aOR = 1.37, 95% CI 1.17–1.61), and a history of prior TB treatment (aOR: 3.75–4.68) were independently associated with higher odds of co-infection. The COVID-19 era (2020–2023) was associated with substantially lower odds of co-infection (aOR = 0.42, 95% CI 0.39–0.46). <bold>Conclusions</bold> HIV prevalence among children with TB in Tanzania declined from 28.5% to 8.9% between 2018 and 2023, temporally coinciding with scaled-up PMTCT, ART and TPT interventions, though this cross-sectional analysis cannot establish causality, the trend is consistent with programmatic success. However, persistent regional disparities, higher risk in older children, and a strong association with prior TB treatment underscore ongoing vulnerabilities that may require more nuanced attention. </p>