By Dr. Maria Simbra

PITTSBURGH (KDKA) — Is something unusual going on with the flu?

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“This year’s flu season started off relatively slowly, sort of an average flu season, but it’s really picked up in the last four weeks,” said Dr. Marc Itskowitz, a primary care internist at Allegheny General Hospital.

The CDC says the percentage of medical visits for flu-like symptoms is up: 4.4 percent, compared to a baseline of 2.2 percent.

“I am a little surprised. Normally in March, there is a decline in the number of cases,” Itskowitz said.

Turns out, the predominant strain has changed since the beginning of the season — H1N1 has shifted to H3N2.

“That tends to correlate with more severe symptoms and hospitalizations,” Itskowitz said.

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But good news if you were immunized this year.

“It does cover the strain that we’re seeing. The overall efficacy was in the 50 to 60 percent range when the CDC did their preliminary analysis,” Itskowitz said. “The majority of patients who are suffering from the flu did not get vaccinated. They’ve told me next year, they will get one. I don’t think it’s unreasonable to get a flu shot at this point, but for most of our patients, they’ve already been vaccinated.”

Allegheny County leads the state in the number of reported flu cases with about 6,000 this season compared to nearly 11,000 last year.

“For every case that gets reported, there’s between 10 and 100 cases that go unreported,” Itskowitz said.

But this month is giving the overall season new shape.

“So last year was the most severe in the last 20 years, in terms of the total number of cases. This March is probably going to be the most severe March that we’ve seen in the last 20 years,” Itskowitz said.

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This pattern of more flu than usual could last a few more weeks. Even with the higher level of flu, it has not been as severe this year compared to recent years.