PHWR Public Health Weekly Report

Objectives: This study aims to examine the mutation status of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in wastewater samples collected from airports and ports, monitor variant trends, and provide baseline data for the early detection of emerging variants.
Methods: Wastewater samples were collected from 13 quarantine stations and tested for pathogens using TaqMan Array Card polymerase chain reaction. Whole-genome sequencing was conducted on SARS-CoV-2–positive samples, and the relative proportions of all SARS-CoV-2 lineages present in the wastewater samples were calculated using the Freyja analytical method.
Results: Analysis of 382 specimens subjected to whole-genome sequencing demonstrated that NB.1.8.1 increased in airport and port wastewater samples after March, reaching a peak prevalence of 64.0% in August. Thereafter, the sublineage PQ.2 increased to 38.9% in November. Conversely, aircraft and ship wastewater samples were predominantly characterized by XFG rather than NB.1.8.1 and PQ.2, in line with global variant circulation trends.
Conclusions: Wastewater surveillance at airports and ports is anticipated to play a complementary role in existing clinical monitoring by allowing the early detection of imported cases and offering continuous monitoring of community transmission.

Objectives: The first National Influenza Annual Report was jointly released by the Korea Disease Control and Prevention Agency (KDCA) and the National Health Insurance Service (NHIS) to provide a comprehensive analysis of influenza activity and the burden of disease during the 2024–2025 influenza season.
Methods: Influenza activity was analyzed using patient- and pathogen-based surveillance data, medical costs data, vaccination coverage, and vaccine effectiveness (VE) estimates. Data were obtained from the KDCA sentinel surveillance system, the National Immunization Program, and the NHIS national health information databases. VE was estimated using both a target trial emulation (TTE)-based retrospective cohort design to assess age-specific outcomes and an interrupted time series (ITS) method with dynamic cohort to evaluate time-varying protection.
Results: During the 2024–2025 season, influenza-like illness peaked at 99.8 cases per 1,000 outpatients in the first week of 2025, the highest level recorded since 2016. The overall influenza virus detection rate was 15.2%, with a winter wave dominated by influenza A and a spring wave of influenza B. NHIS claims identified approximately 3.86 million influenza cases, indicating a decline from the previous season. Despite this decrease in case numbers, total medical costs continued to increase in the post-coronavirus disease 2019 period, reaching 629.5 billion KRW, with hospitalization accounting for 77.3% of the total costs. Vaccination coverage was 70.0% among children aged 6 months to 13 years and 81.6% among adults aged 65 years and older. The TTE analysis showed that VE against severe outcomes ranged from 63.7% to 74.6%, whereas VE against mortality ranged from 52.2% to 81.1%, depending on the age group. The ITS method demonstrated that protection against hospitalization (VE 41.8%) persisted for up to 2 months after vaccination, whereas protection against mortality (VE 38.1%) persisted for up to 6 months. Overall, influenza vaccination was estimated to have prevented 143,868 influenza cases, including outpatient and inpatient cases, as well as 3,506 deaths.
Conclusions: The findings presented in this annual report provide scientific evidence for optimizing national influenza prevention and response strategies and advancing immunization policy.

Objectives: Allergic diseases are chronic, recurrent conditions that can significantly impair daily functioning and quality of life. Accordingly, sustained prevention, early diagnosis, and effective management are essential for reducing their burden on individuals and the healthcare system.
Methods: The World Allergy Organization (WAO) conducts the annual World Allergy Week campaign to increase global awareness of allergic diseases and promote timely diagnosis, appropriate treatment, and ongoing management.
Results: The WAO selected “Allergy care is essential care” as the theme for World Allergy Week 2026, emphasizing the need to recognize allergy prevention, diagnosis, treatment, and long-term management as fundamental components of comprehensive healthcare.
Conclusions: The Korea Disease Control and Prevention Agency has adopted the slogan “Allergy management is not an option, but a necessity,” and plans to implement a range of public awareness initiatives in collaboration with local governments, including quiz events, promotional booths, and hands-on educational activities.