1. Swine Flu (H1N1) FAQ Slideshow Pictures
2. Strep or Sore Throat Slideshow Pictures
3. Flu Fighter Foods Slideshow Pictures

Medical Author:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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In this Article

• Swine flu (H1N1 influenza virus) facts
• What is the swine flu (novel H1N1 influenza A swine flu)?
• What causes swine flu (H1N1)?
• Why is swine flu (H1N1) now infecting humans?
• What are the symptoms of swine flu (H1N1)?
• How is swine flu (H1N1) diagnosed?
• What is the treatment for swine flu (H1N1)?
• What is the history of swine flu (H1N1)?
• What are the risk factors for swine flu (H1N1)?
• Can novel H1N1 swine flu be prevented with a vaccine?
• Can H1N1 be prevented if the H1N1 flu vaccine (or other flu strain vaccine) is not readily available?
• Is swine flu (H1N1) a cause of an epidemic or pandemic in the 2009-2010 flu season?
• What is the prognosis (outlook) and complications for patients who get swine flu (H1N1)?
• Where can I find more information about swine flu (H1N1)?
• Swine Flu (H1N1) FAQ Slideshow Pictures
• Pictures of Strep or Sore Throat - Slideshow
• Flu Fighter Foods Slideshow Pictures
• Patient Comments: Swine Flu - Symptoms and Signs
• Patient Comments: Swine Flu - Concerns
• Swine Flu Index

In 1976, there was an outbreak of swine flu at Fort Dix. This virus is not the same as the 2009 H1N1 outbreak, but it was similar insofar as it was an influenza A virus that had similarities to the swine flu virus. There was one death at Fort Dix. The government decided to produce a vaccine against this virus, but the vaccine was associated with neurological complications (Guillain-Barré syndrome) and was discontinued. Some individuals speculate that formalin, used to inactivate the virus, may have played a role in the development of this complication in 1976. There is no evidence that anyone who obtained this vaccine would be protected against the 2009 swine flu virus. One of the reasons it takes a few months to develop a new vaccine is to test the vaccine for safety to avoid the complications seen in the 1976 vaccine. Individuals with active infections or diseases of the nervous system are also not recommended to get flu vaccines.

Early in the spring of 2009, H1N1 flu virus was first detected in Mexico, causing some deaths among a "younger" population. It began increasing during the summer 2009 and rapidly spread to the U.S. and to Europe and eventually worldwide. The WHO declared it first fit their criteria for an epidemic and then, in June 2009, the WHO declared the first flu pandemic in 41 years. There was a worldwide concern and people began to improve in hand washing and other prevention methods while they awaited vaccine development. The trivalent vaccine made for the 2009-2010 flu season offered virtually no protection from H1N1. New vaccines were developed (both live and killed virus) and started to become available in September-October 2009. The CDC established a protocol guideline for those that should get the vaccine first. By late December to January, a vaccine against H1N1 was available in moderate supply worldwide. The numbers of infected patients began to recede and the pandemic ended. However, a strain of H1N1 was incorporated into the yearly trivalent vaccine for the 2010-2011 flu season because the virus was and is still present in the world populations.

As stated in the first section of this article, a new strain of swine flu, (H3N2)v, was detected in 2011; currently it has not affected any large numbers of people in the 2011-2012 flu season. Researchers have begun development of a specific vaccine for (H3N2)v as a precautionary measure in case this strain predominates in either the end of the 2011-2012 flu season or increases in the 2012-2013 flu season.