Subclade K influenza virus starts spreading early in Japan, may impact the U.S.

Dec. 2 (UPI) -- A newly identified influenza strain, known as Subclade K, is currently spreading across Japan and could pose a notable threat to the United States as the winter flu season begins. This strain is a variation of the type A influenza virus, which typically emerges at the onset of flu season and is later followed by type B infections, according to The Japan Times.

Subclade K has already led to a surge in flu cases in Japan, as well as in Canada and the United Kingdom, and is now beginning to appear in the United States. Research by the Japan Institute of Health showed that 22 out of 23 patient samples collected since September tested positive for the Subclade K strain, a 96% detection rate, reported Nippon.com. Despite its spread, the strain is not linked to more severe symptoms or significantly higher transmissibility compared with other influenza variants, according to JIHS officials.

The Japanese health ministry recorded 196,895 flu cases across roughly 3,800 medical facilities by November 23, averaging more than 51 patients per facility. This number surpasses the threshold of 30 patients per facility that triggers a national flu alert and far exceeds last years average of 2.36 patients per facility. The early surge in flu cases is partly attributed to Subclade K coinciding with the period when most Japanese citizens receive flu vaccinations, leaving many unprotected and more susceptible to infection.

Last year, Japan's flu season reached its peak with an average of 64.39 patients per facility.

Author: Sophia Brooks