New H3N2 flu strain hits the US

"A new and potentially more severe variant of the flu, known as H3N2 subclade K, has reached the United States, prompting heightened vigilance from public health officials as the holiday season and winter travel approach.
According to the Centers for Disease Control and Prevention’s (CDC) flu report, there have already been at least 650,000 illnesses, 7,400 hospitalizations, and 300 deaths from flu this season, ending the week of November 15.

“There is basically a new variant of influenza circulating that has mutated a little bit,” Caitlin River, epidemiologist at Johns Hopkins told NPR. “And that means that it’s just different enough from what your body or the vaccine may recognize that it can kind of get around those protections.”
The emergence of the H3N2 subclade K variant has led experts to warn that this flu season could be particularly severe.
The strain, which has dominated outbreaks in Japan, the United Kingdom, and Canada, is showing signs of spreading rapidly in the U.S. where vaccine uptake is also lagging.
The H3N2 subclade K strain first appeared in Japan and the U.K. before spreading rapidly throughout Canada, where it is now the dominant flu subtype and responsible for a rise in hospitalizations, particularly among the elderly and children.
According to the European Centre for Disease Prevention and Control, the strain has been detected on all continents since May 2025 and accounted for nearly half of H3N2 cases in the European Union (EU) by November.
Flu activity in the U.S. has increased quickly in recent weeks, with most current cases attributed to Influenza A H3N2, and about half linked to subclade K.
The symptoms of H3N2, including its mutated subclade K, are similar to typical flu infections—fever, cough, runny nose, fatigue, muscle aches, and chills. However, reports from international outbreaks show this variant tends to cause more severe illness, particularly among the elderly and young children, sometimes resulting in higher fevers and more frequent complications." msn