The Centers for Disease Control and Prevention is warning of a flu season worse than last year.  And now, a new study in the Journal of Clinical Virology is revealing how cold weather and the spread of viruses, like influenza, are related.

The new research, done over a three year period in Sweden, revealed seasonal flu outbreaks first appeared each year about a week after the winter's first cold spell.  A common finding was with the weather.  Each year, after this first really cold week with below freezing temperatures and low humidity, the flu spread actively.  It turns out airborne particles containing liquid and virus, from a sneeze for example, can spread more easily in cold and dry weather.  This dry air absorbs moisture from the particles, shrinking them and helping them stay in the air longer and travel longer distances.

It is interesting to point out though, the virus behind the common cold didn't seem to be affected by the weather or the season. Also, cold weather isn't the only prerequisite for flu epidemics.  There have to be enough people susceptible to the infection. 

Scientists are quick to mention more research needs to be done in other climates to find out whether this is a consistent phenomenon or just something unique to Sweden.

In the meantime, you're urged to take the proper precautions to prevent getting the flu, including covering your mouth when coughing or sneezing, washing your hands frequently, and getting an annual flu shot.