Influenza, commonly called “the flu,” is caused by a virus that easily spreads from infected persons to the nose and throat of others.  Symptoms of the flu include fever, cough, sore throat, headache, muscle ache, chills, and general malaise.  

The Center of Disease Control and Prevention (CDC) estimates that each year in the US, 5% to 20% of the population gets the flu, more than 200,000 people are hospitalized from flu complications, and 36,000 people die from influenza.

Most infected people who are otherwise healthy will be ill with influenza for a few to several days, resulting in many costly days of missed work.  A 2001 cost-benefit analysis published in the Archives of Internal Medicine estimated productivity losses due to influenza.  The average lost work days were reported at 2.8-3.4 days per episode of influenza, not to mention the people who come to work sick with the flu, thereby lessening their productivity while infecting other employees.