The Japanese government announced on Friday that the average number of influenza patients at designated medical institutions nationwide has hit warning levels at the fastest pace in 10 years. Experts point to the rising number of inbound tourists as a likely factor in the epidemic's earlier-than-usual spread. The figure rose 1.73 times higher than the previous week.
Across roughly 3,000 designated medical institutions nationwide, 145,526 influenza patients were reported during the week from November 10 to Sunday, averaging 37.73 people per facility and surpassing the warning level of 30. According to the Ministry of Health, Labor and Welfare, this figure is 1.73 times higher than the previous week, meaning the warning level was reached five weeks earlier than last season, with 24 of Japan's 47 prefectures exceeding the threshold.
The most commonly reported virus was the type-A Hong Kong strain, the same one that widely circulated during the winter of 2023. Reiko Saito, a professor at Niigata University, said, "The strain was circulating between August and September in Hong Kong and Taiwan, and an increase in tourists traveling to Japan from those regions may have contributed to its rapid spread." She added that other possible factors include "the rapid drop in temperature, poor ventilation, and the extreme temperature fluctuations." "Currently, the outbreak is mainly among children and students, but the number of adults infected is expected to increase toward the end of the year, when people will be on the move more frequently."
By prefecture, Miyagi Prefecture in northeastern Japan recorded the highest number at 80.02, followed by Saitama at 70.01 and Fukushima at 58.54. While eastern Japan saw a rapid rise in general, the lowest numbers were in Kochi, Tokushima, and Kagoshima prefectures. Influenza outbreaks typically occur in winter and the end of spring in Japan. A total of 5,777 elementary, junior high, and high schools have closed or partially closed due to the epidemic, an increase of about 2,000 from the previous week.