Feeling under the weather? You could have Influenza Type A. Here's the difference between Influenza Type A and Type B.

One type mutates often and causes seasonal pandemics. The other one doesn't. Here's what else is different.

Influenza A, B, C Or D? Flu spreads easily in winter due to crowded indoor spaces, low humidity, and reduced immunity.

Flu season is starting to tick up in the U.S. And, looking at clues from other countries, we may be in for a rough winter. But not all influenza is the same. And there are some notable differences ...

Vaccines still are effective in decreasing the possibility of hospitalization associated with this season's "super flu," ...

Is it flu A or flu B, and how long is it contagious? Here's what to know about the flu virus running rampant in New Jersey, symptoms, more.

All viral activity benchmarks have gone down, except for a slight increase in the death rate. Here's what to know about the state of the flu season.

Add Yahoo as a preferred source to see more of our stories on Google. This flu season has been harsh. As of Dec. 27, there have been 11 million reported cases, 120,000 hospitalizations, and 5,000 ...