Influenza: Swine (H1N1), Seasonal, Avian and Pandemic
The word "flu" is used to describe upper respiratory infections caused by influenza viruses. Symptoms include fever, cough and body aches. Flu can sometimes be a severe illness.
Every year in the United States, 5 to 20 out of every 100 people get the flu. More than 200,000 people are hospitalized from flu complications. About 36,000 people die from flu, mostly among the elderly, the very young, and other high-risk groups.
SWINE FLU
For information on swine flu (also called H1N1 flu), please read the March of Dimes article or visit the Web site of the U.S. Centers for Disease Control and Prevention (CDC).
SEASONAL INFLUENZA
Flu viruses spread widely in the U.S. every winter, causing mild to severe respiratory illness. Flu symptoms are similar to those of the common cold: cough, sore throat, body aches. But the ill person also typically has high fever, headache and extreme fatigue. Some sufferers, especially children, have nausea, vomiting and diarrhea.
Complications of flu, such as pneumonia, can be serious and even fatal. People at high risk of complications include infants, pregnant women, the elderly, and those with various chronic health problems, especially of the heart or lungs. For more on maternal and child health issues, see Flu and Pregnancy and Flu and Your Baby.
Who Should Get the Flu Shot?
The main way to prevent the flu is the flu shot. It is best to be immunized during the fall before flu season begins. Annual immunization is recommended for people who are at high risk for flu complications or who may transmit flu to high-risk people.
The U.S. Centers for Disease Control and Prevention (CDC) recommends that all children between the ages of 6 months and 18 years receive a flu shot.
Immunization is essential for some children who are at increased risk of flu complications:
- Children aged 6 months to 4 years
- Children who have certain chronic heart, lung, kidney, blood or metabolic conditions. Examples: asthma, diabetes.
- Children whose immune systems are suppressed. Examples: children taking certain medications or who have been infected with HIV, the human immunodeficiency virus.
- Children who have a condition that can compromise their respiratory system. Examples: spinal cord injury, seizure disorders, cystic fibrosis.
Children who are receiving long-term aspirin therapy. These children might be at risk for Reye syndrome after immunization. Reye syndrome is an extremely rare but serious illness that can affect the brain and liver.
Children who live in chronic-care facilities. Example: children hospitalized for cancer treatment.
Adults who are at high risk of flu complications or who have close contact with persons at high risk should also get a flu shot. Some groups are of special concern:
- Women who are or will be pregnant during the flu season.
- Household contacts and caregivers of children 5 years or younger and adults 50 years or older. It’s especially important for anyone in contact with a child 6 months or younger to be immunized.
- Household contacts and caregivers with any medical condition that puts them at high risk for severe complications for the flu.
- Persons 50 years or older.
Persons who have certain chronic heart, lung, kidney, blood or metabolic disorders. Examples: asthma, diabetes.
Persons whose immune systems are suppressed. Examples: adults taking certain medications or who have been infected with HIV, the human immunodeficiency virus.
Persons who have a condition that can compromise their respiratory system. Examples: spinal cord injury, seizure disorders.
Residents of nursing homes and other chronic-care facilities.
Health care personnel.
Reducing the Risk
CDC emphasizes these common-sense ways to avoid catching the flu and other infections:
- Avoid close contact with people who are sick.
- When you are sick, keep your distance from others to protect them from getting sick.
- If possible, stay home from work, school, and errands when you are sick. You will help prevent others from catching your illness.
- Cover your mouth and nose with a tissue when coughing or sneezing. It may prevent those around you from getting sick.
- Wash your hands often to help protect you from germs.
- Avoid touching your eyes, nose or mouth. People often get sick when they touch something that is contaminated with germs and then touch their eyes, nose or mouth.
- Practice other good health habits. Get plenty of sleep. Be physically active. Manage stress. Drink plenty of fluids. Eat healthy food.
Drugs That Can Fight Flu Viruses
Getting a flu vaccine each year is the best way to protect a person from the flu. Some drugs can also fight flu viruses. They can be used to treat the flu or to prevent infection with flu viruses. These drugs must be prescribed by a health care professional.
In 2008, the CDC recommended two flu drugs:
- Oseltamivir (Tamiflu) is approved to both treat and prevent flu in people 1 year and older.
- Zanamivir (Relenza) is approved to treat flu in people 7 years and older and to prevent flu in people 5 years and older.
The safety of these drugs during pregnancy is unknown. Women who are pregnant or who may become pregnant should discuss options with their health care provider.
PANDEMIC FLU
Pandemic flu is a very serious type of flu that causes a global outbreak known as a "pandemic." Because people have little natural immunity to the virus causing the flu and because, at first, no effective vaccines are available, the disease can spread easily from person to person.
The United States usually faces about three pandemics during a century. The last occurred in 1968.
An especially severe influenza pandemic can lead to high levels of illness and death. Also, because many people cannot work or attend school, society is disrupted and economic losses can be high.
During a pandemic, children and pregnant women are at high risk of serious complications and even death if they become ill with the flu. The risk-reduction practices described above for seasonal influenza are especially important during a pandemic.
According to the CDC, once a vaccine has been developed for the virus causing the pandemic, pregnant women and children from ages 6 to 35 months would be given highest priority for receiving the vaccine.
The CDC has developed extensive plans for minimizing the impact of pandemic flu. The March of Dimes is working closely with CDC to help the public and businesses plan for and deal with a pandemic. The U.S. government's Web site on pandemic flu is an excellent source for more information.
BIRD OR AVIAN FLU
Wild and domesticated birds can carry a wide range of flu viruses. Most of these viruses do not infect humans. One type of bird flu (H5N1) is deadly to domestic fowl. H5N1 can be transmitted from birds to humans and can cause serious illness and even death. Vaccine for H5N1 is very limited.
As of now, H5N1 flu has not occurred in the United States. People catch this flu almost always from close contact with sick poultry. In very rare cases, people appear to have caught the virus directly from others who were infected by poultry.
Since the disease doesn’t spread easily among humans, no epidemic can occur. But H5N1 might spread easily if the virus were to undergo major genetic changes. The result could be a pandemic—a worldwide epidemic of severe disease. For more information, visit the avian flu Web site of the World Health Organization.
REFERENCES
American Academy of Pediatrics. Caring for Your Baby and Young Child, New York, Bantam Books, 2004.
Centers for Disease Control and Prevention. Flu Terms Defined. Downloaded September 10, 2008.
__________. Pandemic Flu: General Information. Downloaded September 10, 2008.
__________. Guidelines for Vaccinating Pregnant Women, May 2007.
__________. Influenza: The Disease. Downloaded September 10, 2008.
__________. Key Facts About Antiviral Drugs and Influenza (Flu). Downloaded September 10, 2008.
__________. Pandemic and Pandemic Threats Since 1900. Downloaded September 20, 2008.
__________. Seasonal Flu: Good Health Habits for Prevention. Downloaded September 10, 2008.
Department of Health and Human Services and Department of Homeland Security. Guidance on Allocating and Targeting Pandemic Influenza Vaccine. Downloaded September 10, 2008.
Fore, A.E., et al. 2008. Prevention and Control of Influenza. MMWR, July 17, volume 57, pages 1-60.
October 2008/April 2009
