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Differences between avian, seasonal, and pandemic flu

Learn how the different types of flu can affect you, and what you can do about them.

About pandemic flu

Pandemic influenza occurs when a new type of human flu virus spreads quickly throughout the world, affecting a lot of people. Since it would be a new virus to people, no one would be immune, and a pandemic could occur. Influenza pandemics have occurred several times in the 20th century, including 1918, 1957, and 1968. 

About seasonal flu

Seasonal flu is caused by several different flu viruses circulating among people. It is called seasonal because it usually happens each year in the late fall and winter, continuing into spring. For healthy children and adults, influenza is typically a moderately severe illness. For people with chronic health problems such as diabetes, asthma, heart or lung problems, influenza can be very severe and even fatal. That’s why flu shots are recommended for many people.

Learn about seasonal influenza from Public Health – Seattle & King County

Differences between avian flu and pandemic flu

Avian flu and pandemic flu are not the same thing. Avian influenza, or "bird flu", is a virus that affects birds. Pandemic flu is human flu that would affect millions of people all around the world. Very rarely, an avian flu virus will infect a person. However, a human pandemic will not happen unless the avian flu virus changes in such a way that it is easy for people to spread the virus from person to person. That would be very dangerous, because people would not have any immunity to this new (to humans) virus. It would take months to develop a vaccine for people for this new virus. Pandemic flu could kill millions of people worldwide.

Risks of avian flu: from birds to humans

It is possible to catch avian flu from birds in parts of the world that have related outbreaks. More than half the people who are known to have contracted avian flu from birds have died, so if avian flu is found in our region it will be important to follow precautions to limit interaction between wild and domestic birds and people.

Do you need an avian flu test?

  • If you are experiencing flu symptoms, bear in mind that unless you had close contact with infected poultry in a country where avian flu is circulating, you would not have been exposed.
  • If you have the flu, only visit the doctor when you would do so under regular circumstances.
  • If you have not traveled recently, there is no need to visit your doctor out of concern about avian flu.
  • If you became ill within 10 days after returning from a country where avian flu is occurring in birds or people, see a health care provider and tell them about your travel history.

Seasonal flu shots do not protect against avian flu

The flu vaccine you get in the fall and winter is for seasonal flu. Seasonal flu vaccine does not protect against avian flu. It is always a good idea to check with your health care provider about getting a flu shot, even if it does not protect you from all influenza viruses.

View seasonal flu and flu vaccine availability in King County.