Overview

• Osaka reported 1.21 influenza patients per sentinel site for September 22–28, marking an earlier-than-usual start to its 2025–26 season.
• The Ministry of Health based its assessment on the national sentinel surveillance system that defines epidemic start at an average of 1.0 patient per facility.
• Osaka noted that some other prefectures have already entered the epidemic phase this season.
• Authorities urged handwashing, cough etiquette, mask use when symptomatic, and early consultation about vaccination to reduce severe illness.
• Osaka also reported elevated RSV activity at 1.82 patients per sentinel site for the same week and will publish weekly Thursday updates on influenza trends.