Influenza, commonly called the “flu,” is a
contagious respiratory illness caused by influenza viruses. Symptoms include
fever, headache, extreme tiredness, dry cough, sore throat, runny or stuffy
nose, and muscle aches. In the United States, influenza is associated with
approximately 200,000 hospitalizations each year. The Centers for Disease Control and Prevention (CDC) estimate that
during the three decades during 1976-2007, influenza-associated deaths ranged
from 3,000 to 49,000 annually.
Everyone 6 months and older should get a flu vaccine as soon as vaccine is
available each fall. Since the virus changes each year it is necessary to
receive a new influenza vaccine each year. People at high risk for complications
• Children aged 6 months to 18 years of age,
• Pregnant women,
• People 50 years of age and older, and
• People of any age with certain chronic medical conditions;
• People who live in nursing homes and other long term care facilities.
People who live with or care for those at high risk
for complications from flu, including household contacts of persons at high risk
for complications from the flu (see above), household contacts and caregivers of
children less than 6 months of age, and health care workers should also be
In addition, practicing good health habits such as
hand washing and covering your nose and mouth when coughing or sneezing may also
prevent the spread of influenza.
If diagnosed within two days of illness, anti-viral
medication may be prescribed to treat influenza (note that antibiotics will not
work as influenza is caused by a virus and antibiotics are only useful for
diseases caused by bacteria).
A note on the
often confusing terminology of “flu:” Technically, “flu” is the disease you get
when you are infected with an influenza virus.
However, there are many other respiratory viruses, such as parainfluenza,
RSV, adenovirus, enterovirus, and human metapneumovirus that can cause the same
symptoms as influenza (fever, cough, sore throat).
Furthermore, many use the term “stomach flu” or “GI flu” to describe
vomiting, nausea, or diarrhea.
However, these symptoms are rarely found with infection by the influenza virus
and they are usually caused by other viruses or bacteria. In these pages, when
we use “flu,” we are referring to the illness caused by infection with influenza
What's happening with flu now
For The Public
For Health Care Professionals
updated Jan 2013