Flu Season Starts Earlier Than Usual in Japan

From Jiji

November 4 2025

TOKYO – Influenza outbreaks have started in Japan in late September, earlier than usual, partly because of increases in cross-border travel. 
   According to the health ministry, the number of flu patients reported by regularly monitored medical institutions across the country in the week to Oct. 26 stood at 6.29 per facility. By prefecture, Okinawa, southernmost Japan, topped the list, with 19.40, followed by three neighboring Tokyo–Kanagawa, with 11.88, Chiba, with 11.82, and Saitama, with 11.73.
   The number began to exceed 1.0 in late September, the second earliest in 20 years, excluding the 2023-2024 season, when outbreaks continued yearlong. A reading of 1.0 or higher suggests the start of a flu season.
   Flu patients fell markedly in and after 2020, thanks to measures against COVID-19.
   But flu outbreaks spread across the country for the first time in three years in late 2022, and the season continued even after summer 2024. In December that year, the number of patients hit the highest level since the current survey method was adopted in April 1999.