In New York City, 57-year-old Judith Quinones suffered her worst case of flu-like illness in years, laid up for nearly a month with fever and body aches. "I just couldn't function," she said.
She decided to skip getting a flu shot last fall. But her daughter got the shot. "And she got sick twice," Quinones said.
On average, about 24,000 Americans die each flu season, according to the CDC.
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.
The last bad flu season involved a swine flu that hit in two waves in the spring and fall of 2009. But that was considered a unique strain, different from the regular winter flu.