Flu Cases Reach Record High in Japan

Japan set a new record of 317,812 weekly influenza cases for December 23–29, 2024, according to figures from the Ministry of Health, Labor, and Welfare, based on reports from 5,000 designated medical institutions across the country. This is the highest total since the current method of keeping records was introduced in April 1999. The average of 64.39 cases per institution is considerably more than the previous high of 57.09 in January 2019.

Kyūshū is particularly hard hit by the current outbreak, with 104.84 cases per medical institution in Ōita, 96.40 in Kagoshima, 94.36 in Saga, 92.56 in Kumamoto, and 90.24 in Miyazaki. All prefectures except Akita, Yamagata, Toyama, and Okinawa exceed the warning level of 30.

The 2020–21 and 2021–22 seasons saw record low numbers of influenza cases. This is thought to be due to the extensive use of masks and washing and disinfecting of hands adopted to contain COVID-19; these measures were also effective against the spread of influenza.

However, the break also led to decreased herd immunity against influenza. The downgrading of COVID-19, so that there were no longer recommendations to wear masks, and renewed freedom of international travel have raised the risks of major influenza outbreaks.

Influenza cases increased for 10 consecutive weeks from the start of the 2024–25 season in November through the record-setting week at the end of December. Seniors, people with underlying medical conditions, and pregnant women are recommended to consider vaccinations. Other useful preparation includes buying painkillers and antifever medicine, and checking the location of the nearest medical institution providing services to outpatients with fevers.

(Translated from Japanese. Banner photo © Pixta.)