Flu usually peaks in midwinter. Symptoms can include fever, cough, runny nose, head and body aches and fatigue. Some people also suffer vomiting and diarrhea, and some develop pneumonia or other severe complications.
Most people with flu have a mild illness and can help themselves and protect others by staying home and resting. But people with severe symptoms should see a doctor. They may be given antiviral drugs or other medications to ease symptoms.
Flu vaccinations are recommended for everyone 6 months or older. Of the 20 children killed by the flu this season, only two were fully vaccinated.
AP Medical Writer Maria Cheng in London contributed to this report.
CDC flu: http://www.cdc.gov/flu/index.htm
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