SIOUX FALLS, S.D. (KELO) — Chances are you know of someone who has been sick recently. According to the South Dakota Health Department, cases of influenza spiked during Christmas and New Year’s, almost certainly because of family and social gatherings. And cases are still high.

Those between the ages of 25 and 49 are the most likely to catch the flu, followed by younger people ages 5 to 24. The Carter family suspects they got sick on a flight to Florida.

“I’ve got a burning throat, I’m completely lethargic, and I got a fever and headache,” Tracy Carter said.

The CDC is monitoring for another surge. Sanford Chief Physician Dr. Jeremy Cauwels says Sanford doctors are seeing more cases of influenza. And he doesn’t believe we have peaked yet in the area. Cauwels says getting vaccinated is proven to be safe and effective.

“I can show you piles of medical literature that says the vaccine does exactly what we want it to and that decreases the number of people that end up in the hospital or dying from the flu,” Cauwels said.

According to Cauwels, there’s still time to get your flu shot. He says protecting your family and friends is always a good reason.

“What we see, unfortunately, you’ll have the flu run through a very young family, and they will all do ok with it, but then an elderly relative will get the flu, and that will be the one that ends up in the hospital. So sometimes the best reason to get the flu shot isn’t so much about you; it is about the other people around you that you love,” said Cauwels.

So far this winter, the flu has put 225 people in South Dakota’s hospitals. Nine of them have died.