Influenza (FLU)

WHAT IS INFLUENZA (FLU) AND HOW IS IT CAUSED?
Influenza is a contagious disease caused by a virus. A virus is a germ that is very small. Influenza viruses infect many parts of the body, including the lungs. When someone who has influenza sneezes, coughs, or even talks, the influenza virus is expelled into the air and may be inhaled by anyone close by.

WHAT IS INFLUENZA (FLU) AND HOW IS IT CAUSED?
Influenza is a contagious disease caused by a virus. A virus is a germ that is very small. Influenza viruses infect many parts of the body, including the lungs. When someone who has influenza sneezes, coughs, or even talks, the influenza virus is expelled into the air and may be inhaled by anyone close by.

IS INFLUENZA CONSIDERED SERIOUS?
For healthy children and adults, influenza is typically a moderately severe illness. Most people are back on their feet within a week. For people who are not healthy or well to begin with, influenza can be very severe and even fatal. The symptoms described above have a greater impact on these persons. In addition, complications can occur. Each year 36,000 Americans die from flu and its complications.
Most of these complications are bacterial infections because the body can be so weakened by influenza that its defenses against bacteria are low. Bacterial pneumonia is the most common serious complication of influenza. In addition the sinuses and inner ears may become inflamed and painful.

WHO GETS INFLUENZA?
Anyone can get influenza, especially when it is widespread in the community. People who are not healthy or well to begin with are particularly susceptible to the complications that can follow. These people are known as "high risk" and should be immunized. For anyone at high risk, influenza is a very serious illness. These populations include those who:2
Have chronic lung disease such as asthma, emphysema, chronic bronchitis, bronchiectasis, tuberculosis, or cystic fibrosis.
Have heart disease.
Have chronic kidney disease.
Have diabetes or another chronic metabolic disorder.
Have any condition that can compromise the respiratory system
Have severe anemia.
Have diseases or are having treatments that depress immunity including HIV infection.
Are residents in a nursing home or other chronic or long-term care facility.
Women who will be pregnant during the influenza season.
All children 6 months through 18 years of age (especially children 6-59 months).
Persons 6 months to 18 years of age receiving chronic aspirin therapy.
Are 50 years of age or older.
Close contacts and health care providers, nurses, or other providers of care to high-risk persons should be immunized to prevent the spread of influenza.Many experts recommend that any person who wishes to avoid or prevent the flu should be vaccinated.

WHO GETS INFLUENZA?
Anyone can get influenza, especially when it is widespread in the community. People who are not healthy or well to begin with are particularly susceptible to the complications that can follow. These people are known as "high risk" and should be immunized. For anyone at high risk, influenza is a very serious illness. These populations include those who:
Have chronic lung disease such as asthma, emphysema, chronic bronchitis, bronchiectasis, tuberculosis, or cystic fibrosis.
Have heart disease.
Have chronic kidney disease.
Have diabetes or another chronic metabolic disorder.
Have any condition that can compromise the respiratory system
Have severe anemia.
Have diseases or are having treatments that depress immunity including HIV infection.
Are residents in a nursing home or other chronic or long-term care facility.
Women who will be pregnant during the influenza season.
All children 6 months through 18 years of age (especially children 6-59 months).
Persons 6 months to 18 years of age receiving chronic aspirin therapy.
Are 50 years of age or older.
Close contacts and health care providers, nurses, or other providers of care to high-risk persons should be immunized to prevent the spread of influenza.Many experts recommend that any person who wishes to avoid or prevent the flu should be vaccinated.

WHAT ABOUT REACTIONS TO THE VACCINE?
Most people have little or no reaction to the vaccine. The most common complaint is soreness at the site where the vaccination was given, usually for less than 2 days. A much smaller number, probably more children than adults, might also develop a slight fever within 24 hours. They may have chills or a headache, or feel a little sick. People who already have a respiratory disease may find their symptoms worsened. Usually none of these reactions lasts for more than a few days. In addition, adverse reactions to the vaccine, perhaps allergic in nature, have been observed in some people. These could be due to an egg protein allergy because the egg in which the virus is grown cannot be completely extracted. These people should be vaccinated only if their health care provider believes it necessary and if the vaccine is given under close observation by a health care provider.

WHO SHOULD BE VACCINATED?
People at high risk should be vaccinated yearly against influenza. In addition, health-care workers, those who provide care to or have household contact with high-risk patients and anyone (including school children) who wants to reduce the risk of getting influenza and its complications or transmitting it to others should be vaccinated. Each year 36,000 Americans die from flu and its complications.
Individuals for whom annual vaccination is recommended include:
All children aged 6 months through 18 years;
All persons 50 years or older;
Children and adolescents (6 months-18 years) receiving long term aspirin therapy;
Women who will be pregnant during the influenza season;
Nursing home and other chronic care facility residents;
All persons with suppressed immune systems, any condition that can compromise the respiratory system, or chronic pulmonary, cardiovascular, renal, hepatic, hematological or metabolic disorders.
Anyone who wishes to prevent influenza and its complications.

CAN YOU HAVE A RECURRENCE OF INFLUENZA?
A person can have influenza more than once. Here's why: The virus that causes influenza may belong to one of three different influenza virus families, A, B or C. Influenza A and influenza B are the major families. Within each influenza virus family, there are many viral strains, like so many brothers and sisters. Both A and B have strains that cause illnesses of varying severity. But the influenza A family has more virulent strains than the B family. If you have influenza, your body responds by developing antibodies. The following year, a new virus family member or a member of another virus family may appear. Your antibodies are less effective or ineffective against this unfamiliar strain. If you are exposed to it, you may come down with influenza again.

HOW ARE INFLUENZA AND COMPLICATIONS TREATED?
For uncomplicated influenza, your health care provider will probably tell you to stay in bed at home as long as the sickness is severe, and perhaps for about two days after the fever is gone. Two antiviral drugs, zanamivir and oseltamivir, can be used for treating someone who develops influenza A or B, particularly if given as soon as possible after the onset of influenza. These drugs also can be used as a preventive measure, but for prevention they must be taken daily as long as influenza cases continue to occur in a community. According to the ACIP guidelines for the 2008-2009 influenza season, neither amantadine nor rimantadine (two older antiviral drugs) should be used for treatment or chemoprophylaxis of influenza A infections. Oseltamivir or zanamivir should be prescribed if an antiviral drug is indicated for the treatment or prevention of influenza.
Your health care provider would have to decide whether to use an antiviral drug either for prevention or treatment. If it is used for treating an early case of influenza, it may shorten this illness and reduce the severity. Some antiviral drugs cause side effects such as difficulty sleeping, nervousness or tremors, depression and gastro-intestinal upset; these are usually mild and often go away even when the medicine is continued. If you should develop a bacterial complication, however, your health care provider can give you an antibiotic.