MINNEAPOLIS - The flu outbreak is gripping Minnesota and the rest of the nation. Experts say, they knew this season would be bad, but it's more intense than predicted.

Right now, 42 states report high patient traffic for the flu. Minnesota, Wisconsin, South Dakota and Iowa are all listed as having widespread outbreaks.

You might think because you've had the flu once, that's it. The bad news is you can catch it again.

"Yes, you can definitely get the flu twice in one year, which is really depressing," said Dr. David Hilden with Hennepin County Medical Center. He says he is seeing a lot more adults in the hospital with the flu compared to years past.

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"The problem with the influenza is there are so many different strains," said Hilden.

There are at least four types of the flu virus, classified as “Influenza Type A”, the predominant and most severe, but there are also “Influenza Type B” strains.

So even if you get sick with one, you can still get infected with the others.

What can you do to protect yourself, from getting it once let alone twice, for starters Dr. Hilden says get a flu shot.

"The flu vaccine this year isn't as effective as we would all hope. Thousands of people this year won't get the flu because they got the vaccine as imperfect as it is," said Hilden.

And how about getting the flu shot twice for extra protection?

"It probably wouldn't be harmful but there's no evidence that it's going to do you much more good after the first one," said Hilden.

Instead, he says take serious precautions like washing your hands often, staying away from anyone that's sick and, again, he emphasizes getting a flu shot.

"It's not just for you. Even if you are healthy adult you get the flu shot for your community," said Hilden.

Doctors typically tell patients they can return to work after at least 24 hours of being free of a fever. But they say you can be contagious for days after.

Find the latest Minnesota flu statistics here.