PHOENIX -- While it hasn't reached epidemic proportions, the flu is fueling fear nationwide as emergency rooms are filled to capacity in many states.
Dr. Oz explains how you can protect yourself even if you haven't gotten the vaccine.
"I'm very worried about the flu this year," he said. "This is the fastest increase in flu symptoms we've had in over a decade."
America's top doctor is weighing in about the flu crisis sweeping the country.
The Centers for Disease Control and Prevention officially classified it the worst since the 2003-2004 season.
"This is an interesting flu year because people this year are a lot sicker than they have been in previous years," said Dr. Jason Knight with Maricopa County Medical Center.
That's because this strain, known as H3N2, has stronger symptoms than the usual flu. Not only that, it stays in your system longer.
"It's especially hitting people with asthma and any type of lung disease like COPD especially hard," Knight said.
Unfortunately, only 32 percent of Americans have been vaccinated and even though this year's vaccine is considered well matched to the H3N2 strain, it only has 60 percent effectiveness rate. Which begs the question, should you bother to get it?
"I know a lot of folks don't believe in the vaccine, don't want to be hassled by it, but we do have the vaccine," Dr. Oz said. "It's not too late to get it."
While Dr. Oz gets the vaccine, he suggests for those choosing not to, "make sure you're sleeping seven to eight and a half hours a day, because that's the best way to keep your immune system strong.
Not only sleep but also sun can be beneficial.
"Get some sunlight," Dr. Oz said. "So go outside today, you're in Arizona, you have the ability to do this. Take your shirt off, if you're a guy, if not, keep something on, get your chest, your back, your legs exposed to the sun. At least take vitamin D, which is the most important of those nutrients."
Arizona is among at least 41 other states reporting widespread flu activity. The Arizona Department of Health Services tracks the number of flu cases and relases a weekly report.