David Goldman, Associated Press
FILE - In this Feb. 9, 2018, file photo, a nurse hooks up an IV to a flu patient at Upson Regional Medical Center in Thomaston, Ga.

SALT LAKE CITY — The Centers for Disease Control and Prevention has reported a second wave of the flu virus is hitting some states in the U.S., including Utah.

While H1N1 was the most common strain of the virus earlier in Utah's season, the H3N2 strain has increased over the past few weeks and accounts for almost 75 percent of subtype influenza A viruses in week 10, according to the Utah Department of Health's latest weekly flu report.

"H3N2 … is a particularly nasty strain of influenza," warned Rebecca Ward, health educator with the department. "It's actually probably a little nastier than the H1N1."

The severity of the state's flu season is considered high, according to the report released Wednesday. However, the severity for the week was ranked moderate.

"It is not unusual to see a second wave of influenza activity caused by a different type of influenza, however, it is normally caused by influenza B instead of the other influenza A strain," the report noted.

Additionally, for the first time this season, the rate of mortality due to pneumonia and influenza was above the epidemic threshold in the ninth week of the season, Feb. 24 to March 3. It dropped back below the threshold in week 10.

So far this season 1,349 people in Utah were hospitalized for influenza-associated reasons, the report states.

Officials are urging Utahns to get the flu shot, which is effective against both the H1N1 and H3N2 strains.

"You're still better off getting vaccinated and it's still not too late," Ward said. "You're looking at three to four different strains of influenza, so you could be protected against all of these even if you had one, there might be another strain that's floating around and you'll want to be protected against that."

It takes 10 to 14 days for vaccines to be effective, Ward added. If people are traveling out of the state or country, they should plan ahead for their flu shot, she advised.

"So you're making sure that immune response is kicked in," she said.

Ward pointed out the influenza virus can be seen into May and added that the department's surveillance period for flu season spans from October to May.

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Nationwide, Utah is one of 32 states experiencing high influenza-like illness activity, according to the CDC.

"So we're hoping that we are on the decline — we're seeing a little bit of a decrease in some of the hospitalizations and influenza-like illness," Ward said. "We just know there's still influenza activity out there."

Officials can't be sure yet when this season's peak will occur, she clarified.

In addition to getting the vaccine, the Utah Department of Health encourages people to wash their hands, stay home when they're sick and take influenza antiviral drugs if prescribed.