The CDC recently issued a health advisory after getting several reports of H1N1 in Michigan.
H1N1, or swine flu as its called, is affecting children and young adults more than older adults.
In 2009, the H1N1 pandemic sickened millions of people and killed more than 12,000 Americans.
Getting vaccinated is a good way to make sure a pandemic like that doesn't happen again.
"We did have one pediatric death already this season, and those are always very tragic because they can be prevented," said Angela Minicuci, a spokesperson for the Michigan Department of Community Health.
Sparrow Hospital said the number of H1N1 cases it has seen has increased dramatically--from five the first week in December, to 38 this week.
McLaren Greater Lansing treated one person for swine flu in December.
Flu season typically peaks in January. Health professionals say that's because it's right after the holidays when people gather, get sick, and then spread out across the country and carry it to others.
"A lot of people in a close setting who are sharing food, drinks, they are touching similar surfaces, so there's a very high chance that people can transmit the virus between each other," said Minicuci.
The H1N1 vaccine is now part of every flu shot, which is another reason you should get yours.
Health professionals say the vaccine is the best defense, and there's no time like the present to get the shot or mist.
"We see a decrease in people coming in the first part of the year because they think that the flu season is over and that's not true. We want people to get vaccinated up through March or April even," said Wendy Ridenour, of the Ingham County Health Department.
Kids and young adults are most at risk, even if they are healthy.
"H1N1 just tends to be a strain that impacts the more healthy population, more so than the traditional flu strains that we see," said Minicuci.
While the flu vaccine takes two weeks to have its full effect, flu season won't end until March or April so there's plenty of time to get the vaccine. Prevention is key.