What causes Flu?

Each winter, influenza spreads around the world. The strains are usually different from one year to the next. That's one of the reasons that you need to be reimmunized for influenza every year.

The two main kinds of influenza viruses are called Type A and Type B .

You can get the flu if you breathe in infected droplets from someone who is carrying the virus. Or, if you touch a contaminated surface, you may transfer the virus from your hand to your mouth or nose.