This year’s very tough flu season may finally be peaking, but it’s not time to let your guard down yet, experts say.

Levels of H3N2—the strain of influenza A that has predominated for most of this flu season and is more likely to cause severe illness than other strains—do appear be falling, according to the latest data from the Centers for Disease Control and Prevention.

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But overall levels of the flu are still quite high across the U.S., says Lynnette Brammer, M.P.H., an epidemiologist with the CDC’s influenza division.

And the percentage of cases caused by influenza B—A and B are the two main flu types—is now on the rise.

“It looks like we’re going into a wave of influenza B right now, which is pretty typical for this time of year,” Brammer says.

Here, what you need to know about influenza B and how to stay sickness-free for the remainder of this nasty flu season.

Flu Type B Can Also Make You Really Sick

Because the most severe flu outbreaks and pandemics (which are caused by new strains) are usually the result of influenza A, some people may think of influenza B as a less severe version of the viral illness. And it’s true that flu B may be less likely to cause hospitalization or death than the H3N2 subtype of flu A.

But a case of influenza B can cause the same level of misery—one to two weeks of fever, chills, cough, head and body aches, fatigue—as any other flu.

A 2014 study in the journal Clinical Infectious Diseases found that there was no difference in the illness severity between people hospitalized for flu A and flu B.

From the symptoms most people have, “you can’t tell them apart,” says Carlos del Rio, M.D., professor of medicine and infectious diseases and professor of global health at the Emory University School of Medicine in Atlanta.

The Flu Vaccine Is Still Worth Getting

According to the CDC’s early data, this year’s flu shot is 36 percent effective against all influenza—but it is 42 percent effective against flu B. And although it may seem late in the season, it’s still a good idea to get the flu vaccine if you haven’t yet, Brammer says.

There are still likely to be several more weeks of high flu activity left. And while the more dangerous H3N2 strain may be on a wane, it’s still the most common flu circulating.

Getting vaccinated is especially important for people older than 65, pregnant women, and anyone who has an underlying health condition such as asthma, heart disease, and more. These are the people who are most likely to get sick enough from the flu to need to be hospitalized.

It’s also vital for children to be vaccinated, particularly those younger than 5, who are more vulnerable to flu complications.

So far 97 U.S. children have died from flu this season, some of them from flu B, according to Brammer. And a study published in 2016 in the journal Pediatrics found that between 2004 and 2013 in Canada, children were slightly more likely to die from a flu B infection than flu A.

Fortunately, this year’s flu vaccine looks to be fairly effective in children, preventing 59 percent of all cases in children between 6 months and 8 years old, according to preliminary data from the CDC. (There’s no breakdown of vaccine effectiveness in kids by flu type.)

You Can Catch Flu B Even If You Had Flu A

If you already had the flu once this season, you can get it again. It’s unlikely that you’ll fall prey to the same strain twice in one season, but you’re not immune to the other circulating strains.

So, in addition to vaccinations, make sure that everyone in your family keeps up with good hygiene practices. That includes diligent hand-washing and covering coughs and sneezes with an elbow or a tissue. And if you do get sick, stay home, to keep from infecting others.