PHWR Public Health Weekly Report

Objectives: Vector surveillance is the cornerstone of malaria prevention and control. This study evaluated malaria vector density and Plasmodium vivax infection among vector mosquitoes in malaria risk areas of the Republic of Korea during 2025.
Methods: From April to October 2025, mosquitoes were collected from 87 surveillance sites. The Korea Disease Control and Prevention Agency, in collaboration with local governments and the Ministry of National Defense, calculated the Trap Index (TI; number of collected individuals/number of traps/collection days). Molecular analyses were performed to detect P. vivax infection in malaria vector mosquitoes.
Results: The cumulative malaria vector TI in 2025 (82.0) decreased by 32.0% compared to 2024, primarily because lower temperatures in April delayed the seasonal peak in vector abundance. The highest proportions of malaria vectors were observed in Gyeonggi Province (36.3%), followed by Gangwon Province (18.8%) and Incheon Metropolitan City (16.9%). Molecular analysis identified four P. vivax-positive mosquito pools, corresponding to a minimum infection rate of 0.19.
Conclusions: Vector surveillance remains a fundamental component of malaria elimination efforts. These findings provide evidence to support the malaria advisory and warning system and offer valuable data for future vector surveillance and malaria control strategies.

Objectives: On March 4, 2026, a respiratory syncytial virus (RSV) outbreak affecting newborns was reported at postpartum care center A in Seoul, the Republic of Korea. An epidemiological investigation was initiated to characterize the outbreak, determine its patterns, and prevent further spread.
Methods: A retrospective cohort study was conducted among the 18 exposed newborns at the postpartum care center to evaluate risk factors for RSV infection. In addition, epidemiological investigations were conducted among all 64 exposed individuals, including parents and staff members, to identify the source and transmission patterns. Cases were defined as individuals whose RSV infection was confirmed by real-time reverse transcription polymerase chain reaction (RT-PCR). Researchers assessed clinical characteristics and exposure factors using the Korea Disease Control and Prevention Agency epidemiological investigation form. Additionally, respiratory and environmental samples were collected for RT-PCR testing.
Results: Of the 64 exposed individuals, 10 tested positive for RSV, yielding an overall attack rate of 15.6%. The attack rate among newborns was 50.0% (9 of 18), consisting of 5 symptomatic and 4 asymptomatic cases. The index case was admitted on February 21, 2026, became symptomatic with sneezing on February 28, and tested positive on March 3. Subsequent cases were identified through March 11. One asymptomatic staff member was also infected without symptoms, whereas all 28 environmental specimens tested negative. This retrospective cohort study identified no significant risk factors associated with RSV infection.
Conclusions: The outbreak demonstrated a high attack rate among newborns, with approximately half of the confirmed cases remaining asymptomatic. In crowded neonatal care settings, timely detection and prompt intervention are essential for preventing further transmission during outbreaks.

Objectives: The coronavirus disease 2019 pandemic demonstrated that responses led solely by public health authorities are insufficient to manage pandemic, highlighting the need for coordinated inter-ministerial collaboration and an integrated, whole-of-government response system. In response, the Korea Disease Control and Prevention Agency (KDCA) developed a framework for pan-ministerial joint exercises for novel infectious disease response in 2024. This report evaluates the feasibility of the framework, analyzes its strengths and areas for improvement identified during implementation, and discusses implications for future pan-ministerial infectious disease preparedness exercises.
Methods: This pilot exercise was jointly planned and implemented by the KDCA and the executing agency, the Infection Control Network. Conducted as a tabletop exercise, it was based on a scenario involving the emergence of novel coronavirus variant, “Omega.” The scenario progressed sequentially from the initial overseas outbreak through the recovery phase. Representatives from nine government ministries and agencies participated in discussions of ministry-specific response measures across each crisis phase. The exercise was evaluated through external experts’ assessments and participant satisfaction surveys.
Results: Participants discussed key government-wide response functions during an infectious disease crisis, including inter-agency roles and responsibilities, information sharing, medical resource management, risk communication, and continuity of essential public services. Overall participation and inter-ministerial collaboration were rated highly. The mean satisfaction score across all evaluation domains was 4.35 points out of 5 (4.35/5.00), with the “exercise environment” receiving the highest score at 4.43 points (4.43/5.00). Participants reported improved understanding of inter-ministerial roles, decision-making processes, and coordination mechanisms. However, opportunities for improvement were identified in resource allocation, information sharing, and policy alignment.
Conclusions: This 2025 pilot exercise demonstrated the practical feasibility of the pan-ministerial joint exercise framework developed in 2024. It represents the first comprehensive pandemic exercise jointly conducted by KDCA and multiple central government ministries. The exercise demonstrated that infectious disease emergency response is a whole-of-government responsibility requiring coordinated action across sectors, including education, public security, and environmental management. It also assessed the operational applicability of existing crisis management manuals and identified priorities for future improvement. Future exercises should expand institutional participation, incorporate diverse outbreak scenarios, be conducted regularly, and be linked to systematic post-exercise monitoring to strengthen national preparedness and response capacity for novel infectious diseases.