<![CDATA[Severe acute respiratory infection syndrome is a major cause of hospitalization and mortality worldwide and remains a critical public health concern in Indonesia. Laboratory-based syndromic surveillance plays an essential role in monitoring circulating respiratory pathogens and detecting emerging threats. To describe the demographic characteristics and temporal distribution of severe acute respiratory infection syndrome cases identified through laboratory-based syndromic surveillance in Indonesia during 2025. We conducted a retrospective descriptive study using routinely collected laboratory surveillance data from the National Biological Public Health Laboratory, Indonesia, during January-December 2025. The cases were defined according to World Health Organization criteria. Specimens submitted through passive syndromic surveillance were tested using polymerase chain reaction-based assays following national protocols. Descriptive analyses were performed to summarize demographic characteristics, laboratory results, and temporal and geographic distribution of the cases. A total of 194 severe acute respiratory infection syndrome cases were identified in 2025. Children under five years of age accounted for 43.8% of cases, and males represented 59.3%. Most specimens were respiratory (94.3%). Overall, 75.2% of cases tested negative for pathogens included in the testing panel. Among laboratory-confirmed cases, Legionella pneumophila (19.1%) and influenza A (8.2%) were the most frequently detected pathogens, while SARS-CoV-2 was detected in one case (0.5%). Severe acute respiratory infection disease cases were reported throughout the year, with fluctuations in weekly case counts and wide geographic distribution across provinces. Severe acute respiratory infection syndrome occurred year-round in Indonesia during 2025, with young children and older adults disproportionately affected. Despite limitations inherent to passive laboratory-based surveillance, these findings demonstrate the value of integrated severe acute respiratory infection disease surveillance for monitoring severe respiratory infections and informing public health preparedness in tropical settings.]]>
