Evaluation of the dengue infection surveillance system in Sawanpracharak Hospital, Nakhon Sawan province, Thailand, January 2023 to November 2024

Abstract

Background: Dengue infection remains a major public health concern both nationally and in Nakhon Sawan Province, as it can manifest in varying degrees of clinical severity. According to epidemiological surveillance data, the morbidity rate in Mueang Nakhon Sawan District in 2024 showed a decreasing trend compared to 2023 but remained higher than the five-year median. Therefore, this study aimed to evaluate the dengue surveillance system at Sawanpracharak Hospital by describing its operational processes, assessing both quantitative and qualitative attributes, and providing recommendations for system improvement

Method: A cross-sectional study was conducted among 797 patients diagnosed with dengue infection or dengue-like illnesses who received care at Sawanpracharak Hospital between January 1, 2023 and November 30, 2024. Participants were selected through stratified random sampling. Medical records were reviewed and analyzed quantitatively, while qualitative attributes were explored through in-depth interviews with 19 staff members involved in the surveillance system.

Results: The weighted sensitivity of the dengue surveillance system at Sawanpracharak Hospital was 58.4%, with a positive predictive value of 99.02%. The timeliness of reports within seven days was 97.9% in 2023 and 98.2% in 2024. Data completeness reached 100% in both years, while data accuracy for variables such as sex, age, nationality, onset date, and diagnosis date exceeded 90%. The representativeness of the system was high, as the characteristics of reported cases closely aligned with those in the hospital database, indicating good consistency and coverage of case reporting. However, accuracy for the “sub-district of residence” variable was relatively lower. The system demonstrated good levels of acceptability, flexibility, and stability, although some difficulties were noted regarding the simplicity of the reporting process.

Conclusions: The quantitative attributes of the dengue surveillance system including sensitivity, positive predictive value, representativeness, timeliness, and data quality were found to be generally good. Qualitatively, the system exhibited good acceptability, flexibility, and stability; however, simplicity remained an area for improvement to enhance overall surveillance efficiency.