For the latest information on influenza vaccination, visit the Centers for Disease Control and Prevention website at

Influenza (also called the flu) is an upper respiratory infection. It is caused by the influenza virus. Flu strains differ from one year to the next. There are two main kinds that infect humans:

  • Type A
  • Type B

You can get the flu when you breathe in droplets from someone infected with the virus. It can also be spread by touching a contaminated surface and then putting your hand to your mouth or nose.

Each year (usually beginning in October), the flu spreads around the world. Anyone can get it. Some people are at a higher risk of complications. People at higher risk of complications include:

  • Being younger than 5 years old
  • Being 65 years old and older
  • Having certain conditions, including:
    • Chronic lung condition (such as asthma)
    • Cardiovascular disease
    • Kidney or liver disease
    • Neurological, blood, or metabolic condition (such as diabetes)
  • Having a suppressed immune system (such as HIV)
  • Being pregnant
  • Being a child or teen who receives long-term aspirin therapy
  • Being American Indian/Alaska Native
  • Being severely obese

Symptoms include:

  • Fever and chills
  • Severe muscle aches
  • Cough
  • Severe fatigue
  • Headache
  • Decreased appetite, other gastrointestinal symptoms (such as nausea, vomiting)
  • Runny nose, nasal congestion
  • Sneezing
  • Sore throat

Treatment may include:

  • Rest
  • Fluids
  • Over-the-counter pain relievers
  • Decongestants
  • Cough suppressants
  • Antiviral medicines