Japan Declares Nationwide Flu Epidemic Amid Early Surge in Cases

Early Declaration Signals Aggressive Flu Season

Japan's Ministry of Health officially declared a nationwide influenza epidemic on October 3, 2025, marking an unusually early start to the flu season. The declaration came after more than 4,000 people were treated for influenza in a single week, specifically 4,030 cases reported at designated medical institutions for the week beginning September 22, 2025. This figure surpassed the epidemic threshold of an average of 1.04 patients per institution.

The outbreak has arrived approximately five weeks earlier than the usual flu season, making it the second-earliest flu outbreak in Japan in two decades.

Impact on Healthcare and Education

The rapid increase in cases has placed a significant strain on Japan's healthcare system, with hospitals reportedly experiencing overcrowding. In response to the escalating situation, at least 135 schools, kindergartens, and childcare centers nationwide have been forced to close temporarily. This number is three times higher than closures reported during the same period last year.

Specific instances of disruption include a primary school in Yamagata Prefecture closing entirely after 22 out of 36 pupils developed flu symptoms. Regions such as Okinawa, Tokyo, and Kagoshima, along with 28 of Japan's 47 prefectures, have reported a rise in cases.

Expert Concerns and Public Health Advice

Medical experts are expressing concern that the influenza virus may be evolving faster and spreading more easily than in previous years. Professor Yoko Tsukamoto from the Health Sciences University of Hokkaido noted that this year's flu wave is 'unusually early and aggressive,' suggesting that 'in the changing global environment this might become a more common scenario.'

Factors contributing to the surge are believed to include the resurgence of mass tourism in the post-pandemic era, which has increased the movement of people and viruses across borders. There is also emerging research indicating that the virus may be developing resistance to conventional treatments.

Health authorities are urging the public to take preventative measures, including frequent handwashing and considering vaccination, particularly for vulnerable groups such as:

• The elderly
• Young children
• Individuals with chronic illnesses

Citizens are advised to avoid unnecessary hospital visits and to consult doctors promptly if flu symptoms appear.