Flu (Influenza) At A Glance

• Influenza, commonly called "the flu," is caused by viruses that infect the respiratory tract.
• Influenza viruses are divided into three types, designated A, B, and C.
  
• Most people who get the flu recover completely in one to two weeks, but some people develop serious and potentially life- threatening medical complications, such as pneumonia.
  
• Much of the illness and death caused by influenza can be prevented by annual influenza vaccination.
  
• Influenza A undergoes frequent antigenic changes that require new vaccines to be developed and people to obtain a new vaccination every year.
  
• Like the influenza virus, drug treatments are constantly changing and improving, but currently, timely vaccination is still considered to be the best defense against the flu.