Flu cases reach their highest level in more than 25 years. How to stay safe.

The United States now has the highest level of respiratory illness since the 1997-98 flu season, according to new data published Monday by the Centers for Disease Control and Prevention.

Approximately 8.2% of recent doctor visits were for flu symptoms, and the CDC estimates that the virus has caused at least 11 million infections, 120,000 hospitalizations and 5,000 deaths, including nine children.

The rapid spread is being attributed to a new strain of influenza A H3N2, called subclade K, Fox News previously reported. It follows a challenging 2025 flu season, which experts say is rare, as bad flu seasons typically do not occur back-to-back.

Experts previously predicted that this flu season would be more severe than some previous ones, due to genetic changes to the virus that made it easier to infect people. The Southern Hemisphere saw a rise in the flu variant last summer — when it’s winter there — during which Australia saw a record-breaking number of flu cases.

While the virus is spreading, there are still things you can do to protect yourself. Here’s what to know.

What are the symptoms of the flu? How is it treated?

There are a range of not-so-fun symptoms of the flu, including fever, muscle ache, cough, headache and exhaustion, according to the Mayo Clinic. Some people also experience GI issues, like vomiting and diarrhea, or ear pain. The only way to know for certain that you have the flu is to take a test, after which your doctor may prescribe antiviral medication that can shorten the duration of the illness.

One clue that you may have the flu is how quickly the symptoms manifest. While the common cold may develop gradually, with a scratchy throat for a day or two before you really feel unwell, the flu can be quite sudden, causing you to feel fine one moment and awful the next.

You can treat the flu at home with rest, liquids to avoid dehydration that can worsen symptoms and over-the-counter fever reducers and pain medication like ibuprofen. However, if you are experiencing severe symptoms like chest pain, confusion, severe dizziness, shortness of breath or dehydration, seek medical attention immediately.

Is a flu shot effective in preventing the new strain of the flu?

While the flu vaccine still protects against severe outcomes from the illness, the current version of the shot is not up to date with the latest strain because the vaccine was formulated before the current strain started circulating.

However, getting vaccinated is still your best chance at preventing severe disease. The vaccine can also help you avoid catching other strains that more closely resemble the one it was formulated for, as different variants still circulate.

“[Vaccines] can prevent serious illness and hospitalization. And they save lives,” said Massachusetts public health commissioner Dr. Robbie Goldstein in a news release, per CNN. “If you have not yet been vaccinated against flu or COVID-19 this season, now is the time. It is not too late. Choosing vaccination is choosing to protect yourself, your family, your friends, your colleagues and your community.”

What else can I do to stay healthy? 

There are simple measures you can take to prevent the flu. The first? Get diligent about washing your hands. The flu typically spreads by droplets — like when people cough, sneeze or even talk — and if those droplets end up on your hands, which end up touching your eyes, mouth or nose, you could get infected. (And it’s never a good idea to share drinks and food with other people during flu season!)

Additionally, you can wear a mask when out in crowded places, or if you are immunocompromised or elderly and want an extra layer of protection.