Your head aches, and so does every muscle in your body. You're
cold one minute and hot the next. Your throat is scratchy and
you're starting to cough. You might be coming down with the flu!
Flu Season Is October to May If you get the flu, you'll have
lots of company. Each year from October to May, millions of
people all across the United States come down with the flu. Kids
get the flu most often. But people in every age group —
including teens — can catch it. What Is the Flu? Flu is the
common name for influenza. It's a virus that infects the
respiratory system. Often when you're sick with a virus, your
body builds up a defense system by making antibodies against it.
That means you usually don't get that particular virus strain
again. Unfortunately, flu viruses mutate (change) each year. So
you aren't protected from getting the flu forever. Some years
the change in the flu virus is slight. So if you do get the flu,
it's mild. The antibodies from having the flu before give you
partial protection. But every 10