How is H1N1 flu different from seasonal flu?

Seasonal flu

• Is caused by influenza viruses that are similar to those already circulating among people.
  
  
• Symptoms include fever, headache, tiredness, dry cough, sore throat, runny nose, and muscle pain.  Deaths can be caused by complications such as pneumonia.  About 9 out of 10 deaths are among those 65 years and older.
  
  
• Healthy adults usually are not at risk for serious complications. The very young, the elderly, and those with certain underlying health conditions are at increased risk for serious complications.
  
  

H1N1 (2009 influenza A virus) flu

• Is caused by a new influenza virus that people have not been exposed to before.
  
  
• Symptoms similar to seasonal flu, but could be more severe, and complications could be more serious. 
  
  
• Healthy adults may be at increased risk for serious complications.