In 1918, millions of healthy farm boys returned from World War I with a deadly cargo -- a new strain of virus that would quickly infect 27% of the people on planet Earth, and within two years kill 50 million people -- three percent of the entire world population. Starting as a cough, the "Spanish Flu" quickly progressed to hemorrhagic pneumonia, causing victims to drown in their own blood.

A century later, the influenza virus is still one of the most deadly pathogens faced by humans, killing as many as 49 thousand people annually in the USA alone, and half a million worldwide. Fortunately, for the 5 to 20% of US citizens that will get the flue this year, typically two days after exposure, the symptoms are likely to be limited to a week of runny nose, sore throat, body aches, fever and painful cough. Don't imagine that your illness will give you pass on next year's bug -- the tricky influenza virus is capable of swapping its chromosomes around as easily as you mix your winter wardrobe, making it impossible to develop a permanent immunity.

In an effort to control outbreaks, the CDC annually formulates the recipe for a vaccine that appears to be the best match to the emerging strains -- with varying results. The Swine flue virus of 1976 caused Guillain-Barre syndrome in hundreds of victims. Four times out of the last 20 years -- including 2007-2008, the vaccine was only weakly effective. However, for health-care workers and the elderly, the vaccine's 70% protection could be a life saver, as well as helping put the brakes on what might otherwise become a runaway epidemic. The CDC recommends all humans older than six months should be vaccinated. Yet even these preparations might prove ineffectual in treating the H1N1 "Bird Flue" strain, that could kill 150 million within a single season. In 2009, the US Government spent $1 Billion preparing for an epidemic that never happened.

Many physicians often prescribe antibiotics for coughs, but like all viruses, the Flu is totally immune to these drugs. However the course of illness can be shortened with antiviral drugs such as Relenza or Tamiflu. Since the flu only lasts a few days, by the time you start your expensive prescription you are probably almost better it anyway -- allowing pharmaceutical companies to take the credit for your "miraculous" recovery.