Archive · 15 Dec 2025
New K Subclade Flu Variant Spreads Rapidly
There's a new type of flu called the K subclade that's spreading quickly in the US.
Doctors are seeing more people with flu symptoms, especially in places like New York City and some other states.
The flu is very active in New York City and high in states like New York, New Jersey, Louisiana, and Colorado.
It's also moderate in Connecticut, Massachusetts, and Rhode Island.
This is happening as flu season gets stronger, and more people are going to the doctor with flu-like symptoms.
The proportion of doctor’s visits for flu symptoms rose to 3.2% for the week ending December 6.
At least 14 public health jurisdictions are showing moderate to high flu activity.
Flu activity is very high in New York City, high in New York, New Jersey, Louisiana, and Colorado, and moderate in Connecticut, Massachusetts, and Rhode Island.
The new K subclade flu variant is rapidly spreading across the US.
The surge in flu activity is part of the broader flu season increase.
- Who
- CDC and public health jurisdictions
- What
- Rapid spread of a new K subclade flu variant
- When
- Week ending December 6
- Where
- Northeast US, including New York City, New York, New Jersey, Connecticut, Massachusetts, Rhode Island, Louisiana, Colorado
- Why
- Flu season surge and increased doctor visits for flu symptoms
- Week Ending
- December 6
- Doctor Visits for Flu Symptoms
- 3.2%
- High Activity States
- New York, New Jersey, Louisiana, Colorado
- Very High Activity Location
- New York City
- Moderate Activity States
- Connecticut, Massachusetts, Rhode Island