New, Severe Flu Variant Spreading Across Illinois and Iowa

Winter is the time for family and friends, holiday fun, and, unfortunately, the spread of the flu in Illinois and Iowa.

It's inevitable, but how bad will each year be, and what kind of flu strain will we need to look for?  The CDC warns that this year, a certain strain is spreading that is even more severe for the elderly and children.

New Mutated Flu Strain: H3N2 'Subclade K'

The new H3N2 flu strain has symptoms similar to the regular flu—fever, chills, body aches, headache, extreme fatigue, congestion, and coughing.  But the difference is that these symptoms start very suddenly.

While the strain is just starting in America, it's been surging in other countries.  Japan declared an influenza epidemic. It's also sweeping through the United Kingdom and Canada.

The H3N2 subclade K has been reported in over half the states, including Iowa and Wisconsin.

According to the CDC's weekly influenza report, overall flu activity is low, but is spreading nationally.  So you can expect more states to report cases soon.

Did you know the CDC also monitors wastewater for the flu?  That's right, they are checking poo for the flu.  As of December 9, the wastewater monitoring is reporting very low levels of influenza, but it is also increasing.

Will A Flu Shot Protect Against This Flu Variant?

Not really.  The flu vaccine for 2025-2026 was formulated for the H1N1, H3N2, and influenza B strains.  This mutated subclade K strain is different from those, and while experts say the vaccine will still provide protection, this year's vaccine is not specifically designed for it.

Doctors still recommend the flu shot for people over 65, young children, and those with underlying conditions.

If the vaccine is not for you, then avoid sick people, wash your hands frequently, and remind those around you to cover their coughs and sneezes.

Welcome to flu season 2025/2026.