A new flu variant is creating surging cases earlier than expected and causing severe illness, experts warn. What you need to know.

‘Tis the season… for coughing, muscle aches and fevers. This year, a new strain of influenza, known as influenza A H3N2 or the subclade K variant, according to Fox News, is spreading rapidly across the globe and in the United States. This week, the Centers for Disease Control and Prevention reported an 8.1% uptick in positive flu tests nationwide, with the new strain leading to a rise in cases and hospitalizations, particularly from the inland western states to the Northeast.

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. And with the Southern Hemisphere seeing a rise in the flu subvariant this summer (which is the Southern Hemisphere’s winter, when the flu tends to circulate) experts believed that the same could happen here once our chillier months arrived. Australia, for example, broke its national record for flu cases this year, amid vaccine hesitancy.

Still, there are 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, per 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, as the vaccine was formulated before the  current strain started circulating.

However, getting vaccinated for the flu is still your best chance at preventing severe disease. It can also stop you from catching other forms of the flu that it’s a better match for, as different variants still circulate, albeit to a lesser degree.

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.