Analysis of the Epidemiological Characteristics and Public Health Response to Healthcare Facility-associated Measles Outbreaks in the Honam Region, Republic of Korea, 2025.

OBJECTIVES

This report aims to analyze the notification processes of source cases, transmission characteristics, and response measures associated with four healthcare facility-associated measles outbreaks that occurred in the Honam region in 2025 and to identify strategies to strengthen future outbreak prevention and response capacity.

METHODS

A retrospective analysis was conducted on four measles outbreaks (Facilities A-D) in healthcare facilities in the Honam region. Data were obtained from the Korea Disease Control and Prevention Agency Integrated Quarantine Information System and epidemiological investigation records. The analysis focused on outbreak timelines, notification processes, transmission patterns, demographic and clinical characteristics, and institutional response frameworks.

RESULTS

Nineteen cases were identified across the four outbreaks. All source cases were unvaccinated children with international travel history. The mean interval from the initial healthcare facility visit to notification was 3.25 days, and the mean interval from rash onset to notification was 1.25 days. Ward transmission occurred while the source cases were hospitalized without isolation because of non-specific prodromal symptoms. Among the 15 secondary cases, 46.7% were healthcare workers who had completed two doses of the measles-mumps-rubella vaccine, indicating breakthrough infections. The Honam Regional Center for Disease Control and Prevention implemented a multi-institutional response that included daily review meetings, contact management, serological testing, and work exclusion of susceptible staff. However, these measures were constrained by staff shortages and limited bed availability, contributing to prolonged outbreaks in some facilities.

CONCLUSIONS

To prevent healthcare facility-associated measles outbreaks associated with imported cases, including international travel history within the recent incubation period, routine assessment of patients with non-specific respiratory symptoms may be necessary. Pre-employment serologic screening of healthcare workers and vaccination based on screening results should also be considered. During outbreaks, flexible institutional strategies and pre-emptive resource allocation are required to minimize healthcare disruption.