ABSTRACT
Hospitals are increasingly challenged by nosocomial infection (NI) outbreaks during the ongoing coronavirus disease 2019 (COVID-19) pandemic. Although standardized guidelines and manuals regarding infection prevention and control (IPC) measures are available worldwide, case-studies conducted at specified hospitals that are required to cope with real settings are limited. In this study, we analyzed three hospitals in Japan where large-scale NI outbreaks occurred for hints on how to prevent NI outbreaks. We reviewed openly available information from each hospital and analyzed it applying a three domain framework: operation management; identification of infection status; and infection control measures. We learned that despite having authorized infection control teams and using existing standardized IPC measures, SARS-CoV-2 may still enter hospitals. Early detection of suspected cases and confirmation by PCR test, carefully dealing with staff-to-staff transmission were the most essential factors to prevent NI outbreaks. It was also suggested that ordinary training on IPC for staff does not always provide enough practical knowledge and skills; in such cases external technical and operational supports are crucial. It is expected that our results will provide insights into preventing NI outbreaks of COVID-19, and contribute to mitigate the damage to health care delivery systems in various countries.