Preventive Response to Avian Influenza Infection in Humans in the Metropolitan Region, 2025-2026

Avian influenza (AI) continues to occur among poultry and wild birds, and human infection with AI viruses can result from exposure to infected birds. The continued occurrence of human cases overseas has highlighted the importance of preventing the introduction and spread of the virus as a major public health priority. This study aims to describe the prevention and response activities for AI human infection in the metropolitan area during the 2025-2026 season and identifies areas for improvement.

In collaboration with public health and livestock departments across four metropolitan jurisdictions, a response task force for human AI infection was established, and a multi-agency hotline system was activated. High-risk groups, including poultry workers, were provided with preventive education. Furthermore, active surveillance and field inspections were conducted among exposed individuals and affected farms.

During the 2025-2026 season in the metropolitan area, 34 highly pathogenic AI outbreaks were reported. Active surveillance was conducted among 3,667 high-risk individuals, including culling workers, poultry farm workers, and response personnel, who completed the 10-day monitoring period without loss to follow-up. Although three suspected cases were identified, laboratory and epidemiologic investigations confirmed that there were no human AI infections.

This study evaluated the operation of an intersectoral system for preventing and responding to human AI infection, highlighting the challenges of managing high-risk groups, particularly foreign workers. Future efforts should strengthen multilingual risk communication and implement surveillance strategies tailored specifically to repeatedly affected areas.