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

Vaccination to prevent influenza is particularly important for people who are at increased risk for severe complications from influenza or at higher risk for influenza-related doctor or hospital visits. When vaccine supply is limited, vaccination efforts should focus on delivering vaccination to the following people since these populations have a higher risk for H1N1 and some other viral infections according to the CDC:

• all children 6 months to 4 years (59 months) of age;
• all people 50 years of age and older;
• adults and children who have chronic pulmonary (including asthma) or cardiovascular (except isolated hypertension), renal, hepatic, neurological, hematologic, or metabolic disorders (including diabetes mellitus);
• people who have immunosuppression (including immunosuppression caused by medications or by HIV);
• women who are or will be pregnant during the influenza season;
• children and adolescents (6 months to 18 years of age) who are receiving long-term aspirin therapy and who might be at risk for experiencing Reye's syndrome after influenza virus infection;
• residents of nursing homes and other long-term-care facilities;
• American Indians/Alaska natives;
• people who are morbidly obese (BMI ≥40);
• health care professionals (doctors, nurses, health care personnel treating patients);
• household contacts and caregivers of children under 5 years of age and adults 50 years of age and older, with particular emphasis on vaccinating contacts of children less than 6 months age;
• household contacts and caregivers of people with medical conditions that put them at higher risk for severe complications from influenza.

The best way to prevent novel H1N1 swine flu is vaccination. The 2010 CDC recommendations include five principal changes or updates in flu vaccinations that include H1N1 as one of the three strains that comprise the current (2011-2012) trivalent seasonal vaccines:

• Routine influenza vaccination is recommended for all people aged ≥6 months. This represents an expansion of the previous recommendations for annual vaccination of all adults 19-49 years of age and is supported by evidence that annual influenza vaccination is a safe and effective preventive health action with potential benefit in all age groups. By 2009, annual vaccination was already recommended for an estimated 85% of the U.S. population, on the basis of risk factors for influenza-related complications or having close contact with a person at higher risk for influenza-related complications. The only group remaining that was not recommended for routine vaccination was healthy nonpregnant adults 18-49 years of age who did not have an occupational risk for infection and who were not close contacts of people at higher risk for influenza-related complications. However, some adults who have influenza-related complications have no previously identified risk factors for influenza complications. In addition, some adults who have medical conditions or age-related increases in their risk for influenza-related complications or another indication for vaccination are unaware that they should be vaccinated. Further support for expansion of annual vaccination recommendations to include all adults is based on concerns that 2009 pandemic influenza A (H1N1)-like viruses would continue to circulate and that a substantial proportion of young adults might remain susceptible to infection with this virus. Data from epidemiologic studies conducted during the 2009 pandemic indicate that the risk for influenza complications among adults 19-49 years of age is greater than is seen typically for seasonal influenza.
• As in previous recommendations, all children aged 6 months to 8 years of age who receive a seasonal influenza vaccine for the first time should receive two doses. Children who received only one dose of a seasonal influenza vaccine in the first influenza season that they received vaccine should receive two doses rather than one in the following influenza season.
• A newly approved inactivated trivalent vaccine containing 60 mcg of hemagglutinin antigen per influenza vaccine virus strain (Fluzone High-Dose [Sanofi Pasteur]) is an alternative inactivated vaccine for people 65 years of age and older.

The CDC occasionally makes changes and updates its information on vaccines and other recommendations about the current flu pandemic. The CDC states, "for the most accurate health information, visit http://www.cdc.gov or call 1-800-CDC-INFO, 24/7." Caregivers should check the vaccine package inserts for more detailed information on the vaccines when they become available.

The CDC says that a good way to prevent any flu disease is to avoid exposure to the virus; this is done by frequent hand washing, not touching your hands to your face (especially the nose and mouth), and avoiding any close proximity to or touching any person who may have flu symptoms. Since the virus can remain viable and infectious for about 48 hours on many surfaces, good hygiene and cleaning with soap and water or alcohol-based hand disinfectants are also recommended. Some physicians say face masks may help prevent getting airborne flu viruses (for example, from a cough or sneeze), but others think the better use for masks would be on those people who have symptoms and sneeze or cough. The use of Tamiflu or Relenza may help prevent the flu if taken before symptoms develop or reduce symptoms if taken within about 48 hours after symptoms develop. Some investigators say that administration of these drugs is still useful after 48 hours, especially in high-risk patient populations. However, taking these drugs is not routinely recommended for prevention for the healthy population because investigators suggest that as occurs with most drugs, flu strains will develop resistance to these medications. During the H1N1 pandemic, the CDC made further suggestions about the use of these antiviral medications and developed the interim guidelines for use of Tamiflu and Relenza as follows:

1. Patients with high-risk factors should discuss flu symptoms and when to use antiviral medications; doctors should provide a prescription for the antiviral drug for the patient to use if the patient is exposed to flu or develops flu-like symptoms without having to go in to see the doctor.
2. "Watchful waiting" was added as a response to taking antiviral medications, with the emphasis on the fact that those people who develop fever and have a preexisting health condition should then begin the antiviral medication.
3. The antiviral medications are the first-line medicines for treatment of novel H1N1 swine flu, and most current cases of flu are novel H1N1 and are, to date, susceptible to Tamiflu and Relenza.

In general, preventive measures to prevent the spread of flu are often undertaken by those people who have symptoms. Symptomatic people should stay at home, avoid crowds, and take off from work or school until the disease is no longer transmittable (about two to three weeks) or until medical help and advice is sought. Sneezing, coughing, and nasal secretions need to be kept away from other people; simply using tissues and disposing of them will help others. Quarantining patients is usually not warranted, but such measures depend on the severity of the disease. The CDC recommends that people who appear to have an influenza-like illness upon arrival at work or school or become ill during the day be promptly separated from other people and be advised to go home until at least 24 hours after they are free of fever (100 F [37.8 C] or greater), or signs of a fever, without the use of fever-reducing medications. The novel H1N1 swine flu disease takes about seven to 10 days before fevers stop, but research data suggests waiting until the cough is gone since many people are still infectious about one week after fever is gone. However, the CDC has not extended their recommendations to stay home for that extra week.