What is influenza (flu)?
Influenza, commonly called "the flu," is caused by the influenza virus, which infects the respiratory tract. The virus is typically spread from person-to-person when an infected person coughs or sneezes the virus into the air. Compared with other viral respiratory infections such as the common cold, influenza infection can cause severe illness and also precipitate serious and life-threatening complications. Typical clinical features include fever, dry cough, sore throat, runny or stuffy nose, headache, muscle aches, and extreme fatigue.
What can people do to protect themselves against the flu?
By far, the single most important preventative measure is to get vaccinated each fall.
Who should get a flu shot?
People 6 months of age and older at risk for getting a serious case of influenza or influenza complications, and people in close contact with them (including all household members) should get the vaccine. An annual flu shot is recommended for everyone 50 years of age and older. This includes people of any age with chronic diseases of the heart, lung, or kidneys or with diabetes, immuno-suppression, or severe forms of anemia. Other groups for whom the vaccine is specifically recommended are residents of nursing homes and other chronic care facilities, and children and teenagers who are receiving long-term aspirin therapy and therefore may be at risk for developing Reye's syndrome after viral infections. Those in close or frequent contact with anyone in a high-risk group should also be vaccinated.
Is the flu vaccine effective immediately after a person receives the shot?
It takes about 1 to 2 weeks after vaccination for antibody against influenza to develop and provide protection.
How well does the vaccine work?
The effectiveness of the flu vaccine in protecting individuals against illness or serious complications of the flu depends on primarily: 1) the age and health status of the person receiving the vaccine and 2) the similarity or "match" between the virus strains in the vaccine and those in circulation. When the "match" between vaccine and circulating strains is close, the flu vaccine prevents illness in approximately 70%-80% of healthy persons younger than age 65 years.
When should I get vaccinated?
The optimal time for vaccination is from October through mid-November.
What are the side effects of the flu?
By far, the most common side effect of the flu vaccine is local arm soreness and swelling. This is usually mild and does not prevent most persons from working. Serious side effects are uncommon and include severe allergic reactions, particularly in people who have a severe allergy to eggs (the vaccine viruses are grown in eggs).
Why must the flu vaccine be given every year?
Influenza viruses are continually changing, which is why the viruses in the vaccine must be updated often. Vaccine for one year may not cover viruses circulating in the next season.
How long is a person with the flu contagious?
This depends on the age of the person, but adults usually can shed influenza virus for up to 3-5 days after they first develop symptoms. Some children may shed the virus for longer than a week.
How do I know if I need an antibiotic?
Viruses cause colds and flu. Antibiotics don't work against viruses. In most cases of a cold or flu, bed rest, plenty of fluids, and an over-the-counter flu medication to relieve your symptoms are the best therapies. Antiviral medications specifically targeted against influenza are available. The exact role of these medications is still being determined. They may be prescribed if influenza is diagnosed promptly. They are most effective if given within 48 hours of initial symptoms, and decrease the duration of infection by approximately 1.5 days.
How can I avoid getting the flu?
During flu season, avoid people with the flu, and wash your hands often. Most viruses are spread by droplets in the air that come from infected people when they talk, sneeze, or cough, or by hand-to-hand contact. Also, smoking while infected with the flu can cause serious complications. Get vaccinated, eat healthy, exercise, and avoid smoking in order to lower your chances of getting the flu.