What is influenza?
Influenza is commonly referred to as "the flu." It is a viral
infection of the lungs. There are two main types of influenza
virus: A and B. Each type includes many different strains that tends to change from year to year.
When does influenza occur?
Influenza occurs most often in the late fall and winter months
in the United States.
Who gets influenza? How is it spread?
Anyone can get influenza, but it is most serious in young
children, the elderly, in people with chronic illnesses (e.g.,
lung disease, heart disease, cancer, or diabetes) or those
with weak immune systems. Influenza spreads easily in discharges
from the nose or throat, usually when an infected person coughs
or sneezes.
How soon after exposure do symptoms appear? What are
the symptoms of influenza?
Symptoms usually appear 1 to 3 days after exposure. Influenza
symptoms can include a sudden onset of fever, headache, chills,
cough, sore throat, and body aches. Diarrhea is not common.
Although most people are ill for less than a week, some people
have complications and may need to be hospitalized.
How is influenza diagnosed and treated?
Laboratory tests are available to diagnose influenza;
however, doctors usually diagnose influenza from the person's
symptoms. Rest, liquids, and over-the-counter medicine (e.g.,
acetaminophen [Tylenol®]) are the usual treatments. Some prescription
drugs may reduce the severity of influenza. Aspirin should not be given to children with fever-causing illnesses because of the possibility of a complication called Reye's syndrome.
How long can a person spread influenza?
Influenza can spread from one person to another beginning
about one day before symptoms appear through about a week
after onset.
Who should be vaccinated against influenza?
All persons aged six months or older should be vaccinated against influenza each year.
Particular effort should be made to immunize people at higher risk for influenza infection or complications. This includes:
• All children aged 6 months-18 years, and all persons aged >50 years
• Pregnant and postpartum women
• Women who will be pregnant during the influenza season
• Residents of nursing homes and long-term care facilities
• People who have chronic lung or heart problems, including asthma
• People who have other serious medical conditions, such as diabetes, kidney disease, cystic
fibrosis, anemia, cancer, weak immune systems
(including those with HIV), or a seizure disorder
To help prevent the spread of influenza to people in high risk groups, those who live with people in a high risk group and healthcare workers who provide care to high risk patients should also receive an annual influenza shot. Travelers to countries outside of the U.S. may also need to consider influenza vaccination.
If I was vaccinated last year do I need a new flu vaccine this year?
Protection offered by the Influenza vaccine typically only lasts for several months. It is therefore important that you receive a new vaccine every year.
What are other steps that can be taken to prevent the spread of influenza?
You can take three important steps to fight the flu: 1) Get vaccinated. 2) Stop the spread of flu and other germs by covering your mouth and nose with a tissue when coughing or sneezing, washing your hands often to help protect yourself from germs, avoiding touching your eyes, nose or mouth, staying home from work, school, and other activities when you are sick, and avoiding close contact with people who are sick. 3) Use antiviral drugs if your doctor recommends them.
Should I be worried about contact with animals?
Influenza viruses are not usually transmitted from animals to humans.
Dogs can become infected with an influenza A (H3N8) virus. This influenza virus can be transmitted from dog to dog, but does not cause illness in humans. More information on canine influenza may be found at: http://www.cdc.gov/flu/canine/.
Birds, including wild birds and domesticated ducks, chickens and turkeys can become infected with influenza A viruses. Most of the avian influenza A viruses do not cause infection in humans. However, some avian influenza viruses can be transmitted to humans and can cause severe illness. Additional information on avian influenza is available at: http://www.cdc.gov/flu/avian/gen-info/facts.htm.
Swine can also be infected with influenza A viruses similar to those found in humans. A small number of swine influenza virus infections occur in humans each year. Most human cases of swine influenza infections have occurred in people who have had contact with swine on farms or at fairs or other livestock shows. Additional information on swine influenza may be found at: http://www.cdc.gov/flu/swineflu/.
What is triple reassortant influenza A (H3N2)v?
Triple reassortant influenza A is a new variant of influenza that has emerged in the swine population. It is a viral infection that has genes from human, swine and bird viruses. From August to December 2011, 12 cases of H3N2v have been identified in five different states. Six of the 12 infected individuals had no identified recent exposure to swine, indicating the possibility for the virus to transmitted animal-to-human or human-to-human. Eleven of the 12 infected were children; however, all individuals have fully recovered with no serious medical complications.
Where can I obtain additional information about the flu?
For more information, visit the Centers for Disease Control and Prevention website (www.cdc.gov/flu/) or talk to a healthcare professional.
