What is flu?

          Flu, or influenza, is a highly contagious acute respiratory illness caused by the Influenza virus. Flu season generally occurs annually all over the world, during the cold season (October to January).

          Influenza infects over 30 million people in the U.S. each year, which is roughly 10% to 20% of the U.S. population. Flu and its complications is the sixth leading cause of death in the U.S., killing 20,000 - 40,000 people a year. As of 1997, it is the fourth leading causes of morbidity or illness in the Philippines. Flu is the most common cause of absenteeism in both school and work.