Japan has declared the start of the flu season on August 28, 2026, the second earliest since 1999. The case rate increased for five consecutive weeks to 1.11, which is 3.5 times the rate for the same week in 2025. Okinawa recorded 4.43 cases, and 41 of 47 prefectures showed an increase. There were 167 sentinel hospitalizations, with approximately half in people over 70 years old. 88% of the typed viruses were A(H1N1)pdm09. Rates remain below historical precaution and alert thresholds.
