With influenza now widespread across the country, doctors are warning people not to ignore the symptoms.
New York City internist Dr. Sonal Parr says it's about timing, not just about aches and fever.
"The key with the flu is that there's sudden onset; you're totally fine and then you're not," she says.
Dr. Parr says you should see your doctor right away because you're contagious up to 48-hours before you even know you're sick.
Flu can develop into life-threatening pneumonia and sepsis, if treatment is delayed, as in the case of a ten-year-old Connecticut boy who died recently.
Flu season can last until May.
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