Health officials are tracking a tough flu season, and one strain stands out.
It is H3N2, with a subtype known as “K” now leading cases in the United States and appearing in the UK as well. Moreover, doctors expect numbers to climb in the weeks ahead.

This variant can hit harder than typical flu. Older adults and people with underlying conditions face the greatest risk. Because of its rapid spread and intensity, many have nicknamed it the “super flu.”

What should you watch for?
Flu tends to arrive suddenly. You may feel extreme fatigue, fever, and chills. H3N2 often brings cough, runny or stuffy nose, sore muscles, and headaches. Some people also experience nausea, vomiting, or diarrhea.

How is it treated?
Most cases improve at home with rest, fluids, and over-the-counter relief. Symptoms usually ease within five to seven days. However, seek medical care if you have very high fever, trouble breathing, chest pain, confusion, or signs of dehydration. As one infectious-disease expert notes, influenza is not “just a cold.”

Where is it showing up?
Public health reports indicate H3N2 subclade K in more than half of U.S. states. Recent data sent to the CDC found that most H3N2 samples since September—about 85 percent—belong to this subtype. Flu activity rose again last week, with hospitalizations and deaths reported nationwide.

In short, stay alert, rest if ill, and contact your clinician if symptoms worsen.