Japan’s flu season hits 5 weeks early amid fears of an evolving virus

The government has declared a nationwide flu epidemic, prompting calls for vaccinations and heightened vigilance

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Elderly shoppers, some wearing face masks, walk through a shopping street in Osaka, Japan, earlier this month. Photo: AFP

Published: 8:00am, 8 Oct 2025Updated: 11:50am, 8 Oct 2025

An unprecedented early surge in influenza cases has compelled Japan’s health authorities to declare a nationwide epidemic, as medical experts warn the virus may be evolving faster and spreading more easily than ever before.

The outbreak, which has caused hospital wards to fill up and schools across the country to close their doors, arrived five weeks ahead of schedule compared with last year.

Such an early and rapid spread suggests the influenza virus is adapting at an unprecedented pace. But this trend is not limited to Japan: researchers globally have observed similar patterns, prompting calls for heightened vigilance among residents and visitors alike.

“The flu season has started really early this year, but in the changing global environment this might become a more common scenario,” said Yoko Tsukamoto, a professor at the Health Sciences University of Hokkaido.

Japan’s Ministry of Health declared an epidemic after more than 4,000 people were treated for influenza in one week. Photo: Shutterstock

Emerging research indicates the virus is not only spreading more efficiently but may also be developing resistance to conventional treatments.

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