It may be spring, but health officials are warning that flu season is not over yet. According to the Centers for Disease Control and Prevention, flu activity in the United States is peaking very late this year.
Twelve-year-old Abigail Bergstrand was hit hard with the flu earlier this month. "The next day I felt terrible," she told CBS news.
Her mother Wendy said she didn't expect Abigail to catch the flu at this time of year.
"Her fever got higher, her energy level was non existent. I was surprised it was the flu in March," she said.
Health officials say that while flu season usually peaks in February, this season is one of the later peaks on record and everyone should still take precautions.
"In the past 19 years, with this year included, we have only had three peaks in March and we have never had an April peak before. So it's a little bit later than normal," said Lynnette Brammer, an epidemiologist at the CDC's Influenza Division.
There have been a mix of flu viruses around this season, but the predominant strain has been the H1N1 virus.
"Viruses that are circulating are similar to those in the vaccines," Brammer said. A close match means the vaccine will be more effective. "Preliminary vaccine effectiveness for this year was close to 60 percent, so for flu that is really good."
The CDC reported Friday that the rate of people seeing their health care provider for influenza-like illness dropped slightly last week, from 3.7 percent to 3.2 percent. Seven states -- Alabama, Kentucky, New Jersey, New Mexico, New York, North Carolina, and Virginia -- and Puerto Rico were experiencing high levels of flu activity.
The most effective way to prevent the flu is by getting a flu shot each year. The CDC recommends everyone 6 months and older get vaccinated.
Abigail didn't have a flu shot. Her doctor prescribed the anti-viral drug Tamiflu, which can lessen symptoms and shorten the illness if taken soon after symptoms appear.
"She was out of school a full week," Wendy said, "and probably by the fifth day of her being sick she was on the mend."
With the season not over yet, experts recommend taking common-sense prevention steps: wash your hands frequently to avoid germs, and stay home if you're sick.