Surgical Site Infections in Tanzania: A Five-Year Trend and Variation Analysis of National Surveillance Data, 2021-2025

Background Surgical site infections (SSIs) are an alarming threat in the surgical field worldwide. They are among the prevalent Hospital Acquired Infections (HAIs) and contribute to antibiotic resistance in resource-limited countries, including Tanzania, where paucity of data exists. This study aimed to ascertain the five-year trend of SSI in Tanzanian health facilities. Methods A retrospective descriptive cross-sectional study was conducted using SSI data reported in the District Health Information System-2 (DHIS2) between October 2021 and December 2025. Data from 138 health facilities were extracted, cleaned, and analysed in R (version 4.5.0). Trends in SSI rates were assessed using Ordinary Least Squares (OLS) regression, with significant variations measured at ≤ 0.05. Results The 138 facilities reported 419,412 surgical procedures during the study period. Most facilities were primary-level (96, 69.6%) and government-owned (119, 86.2%). The number of reporting facilities increased from 17 in 2021 to 138 in 2025, with an increase in surgical procedures from 9,616 to 127,039. Overall SSI rates declined from 3.1% in 2021 to 2.4% in 2025. Primary-level facilities had the highest overall SSI rate (5.4%), declining from 4.7% to 4.0%. In contrast, SSI following section increased from 1.8% to 2.0%. Organ/space SSI showed a statistically significant declining trend from 1.2% to 0.3% (slope = -0.23%/year; 95% CI: -0.34 to -0.12; p = 0.006). The trends in overall SSI rates by level of health facility and ownership were not statistically significant Conclusion Between 2021 and 2025, overall SSI rates decreased despite a substantial increase in surgical volume, suggesting improvement in IPC. While an organ/space SSI significantly decreased, SSI rates due to caesarean section persistently increased, with higher rates reported in primary healthcare facilities, highlighting the need for strengthened perioperative IPC measures in obstetric care and SSI surveillance across primary-level facilities.