1. Swine Flu (H1N1) FAQ Slideshow Pictures
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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, Chief Medical Editor

Melissa Conrad Stöppler, MD, Chief Medical Editor

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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Swine flu, both H1N1 and H3N2v, cause a respiratory infection. The CDC recommends that swine influenza be considered in people who have fever and respiratory symptoms, especially cough or a sore throat. Ill people may also have fatigue, chills, headache, or body aches. Nausea, vomiting, or diarrhea has also occurred in people with swine flu. Very young children may not complain of fever or have a cough but rather have listlessness or shortness of breath as their main symptom.

Children and young adults (ages 0-24 years) had the highest rate of infection with the 2009 H1N1 flu. Older adults (>65 years) were less likely to have infections, leading some to speculate that older individuals might have "partial immunity." Partial immunity occurs when people make antibodies against one virus that have some effect on another virus. Thus, older people who were exposed to a similar virus may have been partly protected against swine flu. The key words here are may and partly. There is no guarantee that an older person is protected, and if they do get infected, they are at risk for complications requiring hospitalization. One recent study showed that 33% of people over age 59 have antibodies that might help protect against novel H1N1. However, if older people do get infected, the disease may be more severe, as is true of most influenza infections.

Although the infection is usually mild, some people with swine flu have experienced serious respiratory illness, including pneumonia or respiratory failure leading to death. Pregnant women are at high risk for severe disease. Of concern, most deaths early in the pandemic occurred in adults under age 65, including people under age 25. This was the opposite of what happens in a normal influenza season when most deaths occur in the elderly.

People with chronic medical conditions are always at higher risk for complications from influenza and this is also true of swine flu. These chronic medical conditions include asthma, chronic lung disease, heart disease, diabetes, suppressed immune systems (including from chemotherapy), and kidney failure.

People with swine influenza are assumed to be contagious from one day before getting sick until at least 24 hours after symptoms resolve. Children and people with weak immune systems may be infectious for longer periods (for example, 10 days).

Currently, the new H3N2v swine flu produces about the same symptoms as the more benign strains of H1N1.

Must Read Articles Related to Swine Flu

Coughs A cough is a symptom of an underlying disease or condition. A chronic or persistent cough may signal certain lung conditions that should be evaluated by a healt...learn more >>

Fever in Adults A fever is a body temperature of 100.4 F or greater. A fever may be caused by a virus, bacteria, fungus, blood clot, tumor, drug, or the environment. Treatment ...learn more >>

Fever in Children Fever is defined as a rectal temperature over 100.4 F or 38.0 C. Fever isn't life-threatening unless it is persistently high -- greater than 107 F rectal temper...learn more >>

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