[Outbreak and Response to Pertussis in a Mental Care Facility in Gyeongbuk, the Republic of Korea].

Objectives: In 2024, the number of pertussis cases increased significantly worldwide, including Republic of Korea (ROK). This report summarizes a pertussis outbreak involving 58 confirmed cases at a psychiatric institution in OO, Gyeongsangbuk-do, ROK, from September 4 to November 1, 2024 and aims to provide insights for future prevention and control measures. Methods: An epidemiological investigation targeting both residents and staff members was conducted at the psychiatric institution to assess the outbreak. Cases were defined as individuals who tested positive for Bordetella pertussis using polymerase chain reaction during the study period. The investigation included mass screening, daily symptom monitoring, isolation, prophylactic antibiotic administration, and vaccination. Descriptive statistics were used to analyze data on symptoms, underlying conditions, and vaccination histories. Results: On September 4, 2024, the first case of pertussis was confirmed through pneumonia screening at another institution, leading to the identification of 58 total cases. The main symptoms included cough (87.9%) and vomiting (5.2%), while 12.1% of cases were asymptomatic. The outbreak primarily affected the second floor, with shared space usage identified as a major transmission factor. Communication barriers hindered symptom recognition and vaccination verification. However, preventive measures, including antibiotics and vaccination, helped minimize further transmission. No additional cases were reported until the end of the surveillance period on November 1, 2024, confirming the successful containment of the outbreak. Conclusions: Effective pertussis control in vulnerable facilities requires verifying vaccination records, administering booster doses when necessary, and implementing proactive screening. This case highlights the importance of early diagnosis and infection control measures.