Known as subclade K, a new, mutated flu strain that has dominated in Europe and Asia is now rapidly spreading across the US.

A novel influenza variant called subclade K appears to be driving an uptick in cases and hospitalizations throughout the U.S. and other countries

A mutated version of the influenza A (H3N2) strain dubbed ‘subclade K’ is spreading in the US and Canada after the UK. Some are calling it the ‘super flu’. How deadly is this variant, which is sending people to hospitals this holiday season?

Ahead of the holiday tourist rush, city health officials in New York City reported nearly 14,000 flu cases in the first week of December.

Doctors say a new H3N2 flu variant is behind rising cases in North Texas. Though the vaccine is a partial match, it still offers strong protection.

Experts share tips to protect children and family members from the flu -- including the subclade K variant -- ahead of the Christmas holiday.

However, getting vaccinated for the flu is still your best chance at preventing severe disease. It can also stop you from catching other forms of the flu that it’s a better match for, as different variants still circulate, albeit to a lesser degree.

It’s actually pretty easy, experts say, because of how abruptly it hits and how bad you feel. One minute you’re fine and the next you’re miserable, with symptoms that can include fever and chills, cough, sore throat, congestion, headaches, body aches and exhaustion. Sometimes the misery also includes nausea or vomiting, especially for children.