A new influenza variant spreading across Japan may be behind the increase in early outbreaks this year, the Japan Institute for Health Security (JIHS) has said.
The new strain, called ¡°Subclade K¡± is a variant of the type A flu virus, which typically spreads around the beginning of the flu season, while type B tends to spread later on.
Of the influenza patients JIHS examined since September, they found that 22 out of 23 samples ¡ª around 96% ¡ª were infected with the new strain.
The risk of developing severe symptoms from Subclade K is no higher than other strains, according to JIHS. The institute also added that the new strain is not necessarily more contagious.
As the flu becomes more widespread, infecting more people, it would mean more people would experience severe symptoms, resulting in more patients being hospitalized. Considering when cases have peaked in previous years, it is very likely that the high levels of infections seen now will continue in the nation, making it necessary for preventative measures to be taken, the JIHS said.
According to the most recent numbers by the health ministry, around 196,895 flu cases were reported by around 3,800 medical institutions during the week through Nov. 23.
On average, there were 51.12 patients per medical facility ¡ª well above the threshold of 30 patients for issuing a warning. During the same period last year, there were only 2.36 patients per medical facility, suggesting the early onset of the flu season this year.
At its peak during the end of December, the flu season from the year prior saw more than 64.39 patients per facility.
Warnings have been issued in 39 prefectures, with the highest rate of patients seen in the Tohoku region.
For prevention on a personal level, the same measures as in the past, such as carefully washing hands, wearing a mask and staying at home when feeling under the weather, are recommended.
Influenza in Japan is seasonal, with the number of cases peaking around January each year. Roughly 90% of cases involve children and adults under the age of 59, but the majority of those hospitalized each year are over 80 or children under the age of 14. Young children in the age group are most likely to die from the flu.
The number of flu cases had dropped dramatically following the COVID-19 pandemic, but returned to pre-pandemic numbers from the 2024-25 flu season.
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