a b s t r a c t a r t i c l e i n f oObjectives: This study aimed to assess the immediate stress and psychological impact experienced by quarantined patients undergoing hemodialysis and university hospital workers who treated patients Middle East respiratory syndrome (MERS) during its outbreak. Design: The group of subjects consisted of 1800 hospital practitioners and 73 quarantined patients undergoing hemodialysis. The Impact of Events Scale-Revised (IES-R) was administered to the practitioners twice, once during the hospital shutdown and again one month after the shutdown. The Mini International Neuropsychiatric Interview and Hospital Anxiety and Depression Scale were administered to patients undergoing hemodialysis. Results: During the initial stages of the MERS outbreak, healthcare workers who performed MERS-related tasks scored significantly higher on the total IES-R and its subscales. In the second assessment of the high-risk group, the sleep and numbness subscale scores from the IES-R differed depending on the implementation of home quarantine, and the intrusion subscale scores differed depending on the performance of MERS-related tasks. Conclusion: Medical staff that performed MERS-related tasks showed the highest risk for post-traumatic stress disorder symptoms even after time had elapsed. The risk increased even after home quarantine. Prompt and continuous psychiatric intervention is needed in high mortality infectious disease outbreaks.