A nasty ‘superflu’ virus is spreading in the U.S. right now: What to know about the subclade K flu variant

For many people, the winter holiday period is their favorite time of the year. It’s weeks full of family, friends, gifts, and cozy indoor get-togethers.

But those social gatherings are among the main reasons why the flu spreads so readily at this time of year. And this year, a so-called “superflu” variant known as subclade K is set to make things even worse.

Here’s what you need to know.

When is flu season?

Flu season is officially in full swing. It’s the time of year when flu viruses are most rampant, and infections tend to spike before finally decreasing and leveling off.

Most people know that flu season usually occurs in the winter months, but the period actually lasts for longer.

According to the Cleveland Clinic, in the northern hemisphere, the flu season starts in October. However, its worst period encompasses December to February, which is when the highest number of cases occur.

Cases usually begin to decline after February, and flu season is typically considered over by May.

But besides its conventional start date, there’s another way to measure when flu season is underway.

As CNN reports, health professionals often use the “epidemic threshold” to measure when flu season is underway. When that threshold, which measures the percentage of visits to a healthcare provider for respiratory illness, rises above 3.1%, flu season is here.

And according to the Centers for Disease Control and Prevention (CDC), the United States passed that threshold last week when it hit 3.2%. And that number is likely to rise in the coming weeks, thanks to a new flu variant circulating the globe called subclade K.

What is the subclade K influenza variant?

The common seasonal flu going around this year is part of the H3N2 family, a strain that has been circulating for decades, notes Gavi, the Vaccine Alliance.

However, a new H3N2 variant has arisen with enough mutations to make it materially different, from a genetic perspective, from the reference strains scientists chose earlier this year to make this year’s flu vaccine.

This variant is called “subclade K.”

Because it has enough genetic differences, the subclade K variant is more resistant to this year’s flu vaccine than other strains.

However, that doesn’t mean this year’s flu vaccine can’t help protect you against subclade K or other flu strains.

As CNN reports, despite this year’s flu vaccine failing to neutralize subclade K viruses as well as other flu strains, the flu vaccine still cuts hospital visits for H3N2 strains in children by 75%. For adults, the vaccine appears to be less effective, but data shows that it can still cut hospital visits by 30% to 40%.

Where in America is the flu most widespread?

According to CDC data for the week ending December 6, the flu virus, including subclade K, is present in most of the United States. The CDC’s Influenza Division’s Weekly Influenza Surveillance report shows that the states with the highest level of flu activity include:

• New York
• Colorado
• Louisana
• New Jersy
• Conneticut
• Idaho

What are the symptoms of the flu?

Common symptoms of the flu include the following, according to the CDC:

• fever or feeling feverish/chills
• cough
• sore throat
• runny or stuffy nose
• muscle or body aches
• headaches
• fatigue (tiredness)
• some people may have vomiting and diarrhea, though this is more common in children than adults.

How can I protect myself against the flu over the holidays?

In winter, people tend to spend more time indoors with windows closed, which allows flu viruses to spread more easily between people. Holiday gatherings can accelerate this spread as many spend more time socializing during the period than they usually do.

But just because it’s flu season doesn’t mean you can’t enjoy the holidays. The CDC offers several bits of advice on how to reduce your risk of seasonal flu, including:

• Getting vaccinated
• Avoiding contact with people who are sick
• Cleaning your hands regularly
• Avoiding touching your mouth, nose, and eyes

And if you think you are sick, you can help protect others by staying home and covering your nose and mouth when you sneeze.