Seasonal Influenza vs. 2009 H1N1 Influenza
What is the difference between seasonal influenza and the H1N1 flu?
Seasonal influenza is caused by viruses that have been interacting with humans for many generations. The human immune system is able to mount a quick immune response when encountering the same seasonal strain(s) again. The new 2009 H1N1 influenza, (formerly known as swine flu) emerged in the spring of 2009. Because humans have never been infected with this strain of the influenza virus, the immune system often cannot react as quickly or effectively as it can with familiar viruses.
While seasonal influenza is most threatening to those with weak immune systems, such as the very young and old, the 2009 H1N1 virus appears to be a threat to healthy, young adults, children and pregnant women. Although the populations most affected differ, the symptoms of seasonal and H1N1 influenza are very similar and can only be distinguished by a medical professional.
Important note about vaccines
The seasonal influenza vaccine will not protect against H1N1 influenza. An H1N1 influenza vaccine has been developed, and was recently approved by the Food and Drug Administration. It is expected to be available in mid-October.
The AMA recommends that you receive both the seasonal influenza vaccine and 2009 H1N1 influenza vaccine as soon as they are available.
Learn more about seasonal and H1N1 influenza.
Sept. 24, 2009