Abstract

Respiratory viral infections remain a significant challenge in school settings, where enclosed spaces and close-contact activities facilitate airborne transmission. This study assessed the effectiveness of a scheduled 250-nanometer ultraviolet-C (UVC) air disinfection intervention in reducing infection rates among students in real-world educational environments.
The intervention was deployed in six actively used classrooms in Nonthaburi, Thailand, encompassing 163 students. Each 30 m² classroom was equipped with an automated UVC air-disinfection system operating for 15 minutes every hour throughout the second semester of the 2024 academic year. Monthly incidence data for influenza and COVID-19 were collected and compared with regional surveillance reports from schools without UVC systems.
Results revealed a consistent and substantial reduction in infection rates within UVC-equipped classrooms (0.00–2.45%) compared to control schools (1–12%) across all months. Notably, zero infections were recorded in September 2024, and during a regional outbreak in February 2025, where control schools reported infection rates as high as 12%, UVC classrooms reported only 2.45%. This reflects a relative reduction exceeding 75% during peak transmission periods.
The intervention functioned without disrupting classroom routines, offering continuous, passive airborne pathogen control. These findings support the integration of scheduled UVC air disinfection as a viable, non-intrusive infection control measure in schools. Widespread adoption may enhance public health resilience, reduce student absenteeism, and serve as a complementary strategy alongside existing preventive practices.