Cold, Flu, & Cough Health Center

Types of Flu

Do Different Types of Flu Viruses Hit the Population Each Year? continued...

According to the CDC, most flu vaccines contains three influenza viruses: one A (H3N2) virus, one A (H1N1) virus, and one B virus (one type of shot protects up to four strains). The viruses in a flu shot and FluMist vaccine change each year based on international surveillance and scientists' estimations about which types and strains of the flu will be most potent that year. Now one type of traditional flu shot has been approved that covers four strains: two types of each A and B flu bugs. 

About two weeks after getting a flu shot or FluMist, antibodies that provide protection against the flu viruses develop in your body.

What Is the Bird Flu?

The avian influenza virus causes bird flu. Birds can be infected by influenza A viruses and all of its subtypes. Yet birds are not capable of carrying either type B or C of the influenza viruses.

There are three main subtypes of avian flu, including H5, H7, and H9. The subtypes H5 and H7 are the most deadly while the H9 subtype is less dangerous.

Which Type of Bird Flu Is in the News?

Health care professionals had been very vocal about the strain of avian influenza known as H5N1. 

The first cases of 2009 H1N1 flu were reported in the spring of 2009. Since the virus was new, most people were are not immune to it, which meant that many more people became sick during that flu season. The virus was very different from the regular flu virus and caused the first flu pandemic in more than 40 years.

The reason H5N1 has caused so much alarm is its ability to pass from wild birds to poultry and then on to people. While wild birds are commonly immune to the devastating and possibly deadly effects of H5N1, the virus has killed more than half of the people infected with it. The risk of avian flu is generally low in most people because the virus does not typically infect humans. Infections have occurred as a result of contact with infected birds. Spread of this infection from human to human has been reported to be extremely rare. 

Should I Worry About Catching Bird Flu?

People in the United States have less to fear than people who live abroad. Most of the illnesses associated with bird flu had been reported in Asian countries among people who have had close contact with farm birds. Also, people are not able to catch the bird flu virus by eating cooked chicken, turkey, or duck. High temperatures kill the virus.

Is There a Vaccine for Bird Flu?

Currently, there is not a bird flu vaccine available to the public. Additionally, it's important to know that the regular influenza vaccine does not provide protection against avian influenza or bird flu.

For in-depth information, see WebMD's Understanding Bird Flu.