Every year, 10 percent to 20 percent of
Americans get sick with the flu (influenza). For most people, the fever, exhaustion, and aches and
pains of the flu can be debilitating for a week or two, but for the elderly and those with
compromised immune systems the flu can be much more serious. An estimated 100,000 hospitalizations
and about 20,000 deaths occur each year from the flu or its complications. A look at three aspects of
the flu can help people understand this illness better.
Are There Different Types of Fly Viruses?
Influenza, or the flu, is a respiratory infection caused by a variety of flu viruses.
The first flu virus was identified in the 1930's. Since then, scientists have classified flu viruses
into types A, B, and C. Type A is the most common and usually causes the most serious epidemics. Type
B outbreaks also can cause epidemics, but the disease it produces generally is milder than that
caused by type A. Type C viruses, on the other hand, never have been connected with a large
How Can People Keep from Getting the
The main way to keep from getting the flu is to get a yearly flu vaccine. The immune
system takes time to respond to the flu vaccine. Therefore, people should get vaccinated six to eight
weeks before flu season begins. This prevents them from getting infected or reduces the severity of
flu if they do get it. They must get the vaccine every year because it changes. Scientists make a
different vaccine every year because the strains of flu viruses change from year to year. Nine to 10
months before the flu season begins, they prepare a new vaccine made from inactivated (killed) flu
viruses. Because the viruses are killed, they cannot cause infections. The vaccine preparation is
based on the strains of the flu viruses that are in circulation at the time. It includes those A and
B viruses expected to circulate the following winter.
Medicine for Prevention
Although the flu vaccine is the best way to prevent getting the flu, three antiviral
medicines also are available by prescription that will help prevent flu infection:
Tamiflu® (oseltamivir), Flumadine® (rimantadine), and Symmetrel® (amantadine). The
decision of which medicine to prescribe is based on patients ages. The Food and Drug
Administration (FDA) has approved Tamiflu® for use in adults and adolescents 13
years and older. Rimantadine and amantadine have been approved for use by adults and children
who are one year of age and older.
These medicines help prevent the flu if people take them for at least two weeks during
the outbreak of flu in their community. They may use either rimantadine or amantadine immediately
following flu vaccination during a flu epidemic to protect them during the two- to four-week period
before antibodies (proteins from the immune system that protect people from the flu virus) develop or
when a flu epidemic is caused by virus strains other than those covered by the vaccine.