Experts Say a Severe New Flu Strain Is Going To Be Everywhere This Year

Flu season typically kicks off in the fall in the U.S., and while the peak season isn't typically until December, those first few months leading up to the busy time for doctors and healthcare providers can tell medical experts a lot about just how bad things are going to get.

According to the pros, it looks like the 2025 flu season is shaping up to be a severe one, thanks to a new flu strain that has been wreaking havoc in places like the U.K. and Japan, both of which are reporting high flu rates.

It looks like the reason things look so bleak for the 2025/2026 flu season may have a lot to do with how many times the new strain has mutated, which seems to have given it some protection against the immunity building vaccines that so many Americans have already gotten.

Want to learn more about what is happening with the new flu strain, including how you can protect yourself from the worst of the illness? Keep reading as we break it down and tell you what you need to know to stay healthy.

It's not unusual to see new flu strains each year. And while some are more notable than others — who can forget the H1N1 outbreak of 2009 — sometimes a new variant has doctors expecting the worst. It sounds like that is exactly what is happening in 2025 with the H3N2 influenza variant.

According to Today, the variant came onto the scene early in 2025, which gave it plenty of time to mutate and adapt to the vaccines people had already gotten.

Part of "subclade K," this variant quickly became the most common one people were being infected by in the Northern hemisphere. As a result, areas of the U.K. and Japan are seeing an earlier start to their flu season, as well as more severe illnesses.

Unfortunately, the U.S. may be at a disadvantage as this flu season begins to ramp up, since important data wasn't collected and monitored during the government shutdown, which means we may not have an accurate picture of what's happening here.

Those who get infected with the 2025 flu variant will likely experience the same types of symptoms as most other flu strains. However, these symptoms may be more severe and may produce worse health outcomes for those high-risk patients. According to the Cleveland Clinic, some of the symptoms include:

• Fever, chills, and body aches
• Cough, sore throat, and nasal congestion
• Headache
• Fatigue
• Vomiting or Diarrhea (typically only seen in children with the flu)

The flu is highly contagious and can cause major disruptions in school and workplace settings. As such, prevention is the best way to manage the flu, and the first step involves getting your annual flu vaccine. Next, maintaining proper personal hygiene is also key. That means washing your hands and covering your mouth when you cough.

Lastly, if you feel sick, stay at home. While you may not be sure whether or not you have the flu, going out in public while you're sick is never a good idea.